Note: This page contains sample records for the topic cosmic ray detection from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

Direct cosmic-ray detection  

NASA Astrophysics Data System (ADS)

One century after the discovery of cosmic rays, many questions remain open on their origin, nature, and transport. Experiments to detect them directly have constantly improved, and are today of highly diversified designs. Indeed, precise measurements of cosmic rays in an energy range from ˜104 to ˜1015eV allow one to study the mechanism of acceleration of primary cosmic rays up to very high energy, to characterise their possible sources, and to clarify their interactions with the interstellar medium. Such measurements of elemental cosmic-ray spectra require complementary and redundant charge- and energy-identification detectors, such as the balloon-borne Cosmic-Ray Energetics And Mass (CREAM) experiment, which measures cosmic rays from 1012 to 1015 eV for all elements up to and including iron. Here I present the current status of direct cosmic-ray measurements, with the focus on the latest CREAM results. Finally, I briefly discuss the cosmic-ray identification above the knee.

Putze, Antje

2012-01-01

2

How to Detect Cosmic Rays  

NSDL National Science Digital Library

In this lesson on cosmic rays, students will explain two examples of a cosmic ray detector. Includes information about student preconceptions and a demonstration that requires a geiger counter and optional access to a small radioactive source that emits energetic helium nuclei (alpha particles), e.g., the mineral the mineral autunite, which contains uranium. This is activity two of four from The Cosmic Ray Telescope for the Effects of Radiation (CRaTER).

3

Detecting EHE Cosmic Rays Using Cherenkov Light  

NASA Astrophysics Data System (ADS)

Cherenkov light has been used to detect gamma rays in the TeV energy range using an imaging technique and cosmic rays in the PeV energy range using a non-imaging technique. We would like to extend the use of the non-imaging technique up to nearly 1 EeV. At these energies the technique can be used in conjunction with fluorescence detection of cosmic rays, allowing for hybrid reconstruction of shower geometries and cross calibration of energy scales. We envision using an array of Cherenkov detectors as part of the Telescope Array (TA) Low Energy extension (TALE), extending the energy range of the detector down to the Knee of the cosmic ray energy spectrum.

Bergman, Douglas

2011-04-01

4

Cosmic Ray Inspection and Passive Tomography for SNM Detection  

Microsoft Academic Search

The Cosmic Ray Inspection and Passive Tomography (CRIPT) project has recently started investigating the detection of illicit Special Nuclear Material in cargo using cosmic ray muon tomography and complementary neutron detectors. We are currently performing simulation studies to help with the design of small scale prototypes. Based on the prototype tests and refined simulations, we will determine whether the muon

John Armitage; Douglas Bryman; Thomas Cousins; Grant Gallant; Andrew Jason; Guy Jonkmans; Scott Noël; Gerald Oakham; Trevor J. Stocki; David Waller

2009-01-01

5

Radio detection of cosmic rays in the Pierre Auger Observatory  

NASA Astrophysics Data System (ADS)

In small-scale experiments such as CODALEMA and LOPES, radio detection of cosmic rays has demonstrated its potential as a technique for cosmic ray measurements up to the highest energies. Radio detection promises measurements with high duty-cycle, allows a direction reconstruction with very good angular resolution, and provides complementary information on energy and nature of the cosmic ray primaries with respect to particle detectors at ground and fluorescence telescopes. Within the Pierre Auger Observatory, we tackle the technological and scientific challenges for an application of the radio detection technique on large scales. Here, we report on the results obtained so far using the Southern Auger site and the plans for an engineering array of radio detectors covering an area of ˜20km2.

Huege, T.; Pierre Auger Collaboration

2010-05-01

6

Soft cosmic ray tomography for detection of explosives  

Microsoft Academic Search

Charged particle tomography has been gaining ground due to its unique probing characteristics, and the ability of cosmic ray muons to deeply penetrate matter, allowing sensitivity to atomic number, radiation length and material density via detection of the probing particles before and after target traversal. But not all particles completely traverse the target volume. This paper explores the usefulness and

L. Cuellar; K. N. Borozdin; J. A. Green; N. W. Hengartner; C. Morris; L. J. Schultz

2009-01-01

7

Student Projects in Cosmic Ray Detection  

ERIC Educational Resources Information Center

The Alberta Large-area Time-coincidence Array (ALTA) study has been in existence for about 10 years under the direction of Jim Pinfold of the Centre for Particle Physics at the University of Alberta. The purpose of the ALTA project is to involve Alberta high schools, and primarily their physics classes, to assist in the detection of the presence…

Brouwer, W.; Pinfold, J.; Soluk, R.; McDonough, B.; Pasek, V.; Bao-shan, Zheng

2009-01-01

8

Fibre laser hydrophones for cosmic ray particle detection  

NASA Astrophysics Data System (ADS)

The detection of ultra high energetic cosmic neutrinos provides a unique means to search for extragalactic sources that accelerate particles to extreme energies. It allows to study the neutrino component of the GZK cut-off in the cosmic ray energy spectrum and the search for neutrinos beyond this limit. Due to low expected flux and small interaction cross-section of neutrinos with matter large experimental set-ups are needed to conduct this type of research. Acoustic detection of cosmic rays may provide a means for the detection of ultra-high energetic neutrinos. Using relative low absorption of sound in water, large experimental set-ups in the deep sea are possible that are able to detect these most rare events, but it requires highly sensitive hydrophones as the thermo-acoustic pulse originating from a particle shower in water has a typical amplitude as low as a mPa. It has been shown in characterisation measurements that the fibre optic hydrophone technology as designed and realised at TNO provides the required sensitivity. Noise measurements and pulse reconstruction have been conducted that show that the hydrophone is suited as a particle detector.

Buis, E. J.; Doppenberg, E. J. J.; Nieuwland, R. A.; Toet, P. M.

2014-03-01

9

Detecting cosmic rays with the LOFAR radio telescope  

NASA Astrophysics Data System (ADS)

The low frequency array (LOFAR), is the first radio telescope designed with the capability to measure radio emission from cosmic-ray induced air showers in parallel with interferometric observations. In the first ~2 years of observing, 405 cosmic-ray events in the energy range of 1016-1018 eV have been detected in the band from 30-80 MHz. Each of these air showers is registered with up to ~1000 independent antennas resulting in measurements of the radio emission with unprecedented detail. This article describes the dataset, as well as the analysis pipeline, and serves as a reference for future papers based on these data. All steps necessary to achieve a full reconstruction of the electric field at every antenna position are explained, including removal of radio frequency interference, correcting for the antenna response and identification of the pulsed signal.

Schellart, P.; Nelles, A.; Buitink, S.; Corstanje, A.; Enriquez, J. E.; Falcke, H.; Frieswijk, W.; Hörandel, J. R.; Horneffer, A.; James, C. W.; Krause, M.; Mevius, M.; Scholten, O.; ter Veen, S.; Thoudam, S.; van den Akker, M.; Alexov, A.; Anderson, J.; Avruch, I. M.; Bähren, L.; Beck, R.; Bell, M. E.; Bennema, P.; Bentum, M. J.; Bernardi, G.; Best, P.; Bregman, J.; Breitling, F.; Brentjens, M.; Broderick, J.; Brüggen, M.; Ciardi, B.; Coolen, A.; de Gasperin, F.; de Geus, E.; de Jong, A.; de Vos, M.; Duscha, S.; Eislöffel, J.; Fallows, R. A.; Ferrari, C.; Garrett, M. A.; Grießmeier, J.; Grit, T.; Hamaker, J. P.; Hassall, T. E.; Heald, G.; Hessels, J. W. T.; Hoeft, M.; Holties, H. A.; Iacobelli, M.; Juette, E.; Karastergiou, A.; Klijn, W.; Kohler, J.; Kondratiev, V. I.; Kramer, M.; Kuniyoshi, M.; Kuper, G.; Maat, P.; Macario, G.; Mann, G.; Markoff, S.; McKay-Bukowski, D.; McKean, J. P.; Miller-Jones, J. C. A.; Mol, J. D.; Mulcahy, D. D.; Munk, H.; Nijboer, R.; Norden, M. J.; Orru, E.; Overeem, R.; Paas, H.; Pandey-Pommier, M.; Pizzo, R.; Polatidis, A. G.; Renting, A.; Romein, J. W.; Röttgering, H.; Schoenmakers, A.; Schwarz, D.; Sluman, J.; Smirnov, O.; Sobey, C.; Stappers, B. W.; Steinmetz, M.; Swinbank, J.; Tang, Y.; Tasse, C.; Toribio, C.; van Leeuwen, J.; van Nieuwpoort, R.; van Weeren, R. J.; Vermaas, N.; Vermeulen, R.; Vocks, C.; Vogt, C.; Wijers, R. A. M. J.; Wijnholds, S. J.; Wise, M. W.; Wucknitz, O.; Yatawatta, S.; Zarka, P.; Zensus, A.

2013-12-01

10

Cosmic Ray Inspection and Passive Tomography for SNM Detection  

SciTech Connect

The Cosmic Ray Inspection and Passive Tomography (CRIPT) project has recently started investigating the detection of illicit Special Nuclear Material in cargo using cosmic ray muon tomography and complementary neutron detectors. We are currently performing simulation studies to help with the design of small scale prototypes. Based on the prototype tests and refined simulations, we will determine whether the muon tracking system for the full scale prototype will be based on drift chambers or extruded scintillator trackers. An analysis of the operations of the Port of Montreal has determined how long muon scan times should take if all or a subset of the cargo is to be screened. As long as the throughput of the muon system(s) is equal to the rate at which containers are unloaded from ships, the impact on port operations would not be great if a muon scanning stage were required for all cargo. We also show preliminary simulation results indicating that excellent separation between Al, Fe and Pb is possible under ideal conditions. The discrimination power is reduced but still significant when realistic momentum resolution measurements are considered.

Armitage, John; Oakham, Gerald [Department of Physics, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6 (Canada); Bryman, Douglas [Advanced Applied Physics Solutions, 4004 Westbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Cousins, Thomas; Noeel, Scott [International Safety Research, 38 Colonnade Rd. N. Ottawa, ON, K2E 7J6 (Canada); Gallant, Grant [Canadian Border Services Agency, Laboratory and Scientific Services Directorate, 79 Bentley Avenue, Ottawa, ON, K2E 6T7 (Canada); Jason, Andrew [Los Alamos National Laboratories, MS H817, Los Alamos National Laboratory, Los Alamos, NM, USA 87544 (United States); Jonkmans, Guy [Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, ON, K0J 1J0 (Canada); Stocki, Trevor J. [Radiation Protection Bureau, Health Canada, 775 BrookfieldRd, A.L. 6302D1, Ottawa, ON, K1A 1C1 (Canada); Waller, David [Defence Research and Development Canada-Ottawa, 3701 Carling Avenue, Ottawa, ON, K1A 0Z4 (Canada)

2009-12-02

11

Towards the installation and use of an extended array for cosmic ray detection: The EEE Project  

Microsoft Academic Search

The Extreme Energy Events (EEE) project started to use an array of cosmic ray telescopes for muon detection, distributed over the italian territory. The use of such telescopes, based on Multigap Resistive Plate Chambers (MRPC) allows the study of the local muon flux, the detection of cosmic ray showers and the search for correlations between distant showers. The project is

M. Abbrescia; A. Alici; S. An; R. Antolini; A. Badalà; Y. W. Baek; R. Baldini Ferroli; G. Bencivenni; F. Blanco; E. Bressan; A. Chiavassa; C. Chiri; C. Cicalò; L. Cifarelli; E. Coccia; F. Coccetti; A. De Caro; D. De Gruttola; S. De Pasquale; M. D'Incecco; F. L. Fabbri; V. Frolov; M. Garbini; C. Guarnaccia; C. Gustavino; D. Hatzifotiadou; G. Imponente; J. S. Kim; M. M. Kim; P. La Rocca; F. Librizzi; A. Maggiora; H. Menghetti; S. Miozzi; R. Moro; F. Noferini; P. Pagano; M. Panareo; G. S. Pappalardo; C. Petta; G. Piragino; R. Preghenella; F. Riggi; F. Romano; G. Russo; G. Sartorelli; C. Sbarra; G. Scioli; M. Selvi; S. Serci; E. Siddi; H. Wenninger; M. C. S. Williams; C. Zampolli; A. Zichichi; R. Zuyeuski

2009-01-01

12

ESA's Integral detects closest cosmic gamma-ray burst  

NASA Astrophysics Data System (ADS)

5 August 2004 A gamma-ray burst detected by ESA's Integral gamma-ray observatory on 3 December 2003 has been thoroughly studied for months by an armada of space and ground-based observatories. Astronomers have now concluded that this event, called GRB 031203, is the closest cosmic gamma-ray burst on record, but also the faintest. This also suggests that an entire population of sub-energetic gamma-ray bursts has so far gone unnoticed... Gamma ray burst model hi-res Size hi-res: 22 KB Credits: CXC/M. Weiss Artist impression of a low-energy gamma-ray burst This illustration describes a model for a gamma-ray burst, like the one detected by Integral on 3 December 2003 (GRB 031203). A jet of high-energy particles from a rapidly rotating black hole interacts with surrounding matter. Observations with Integral on 3 December 2003 and data on its afterglow, collected afterwards with XMM-Newton, Chandra and the Very Large Array telescope, show that GRB 031203 radiated only a fraction of the energy of normal gamma-ray bursts. Like supernovae, gamma-ray bursts are thought to be produced by the collapse of the core of a massive star. However, while the process leading to supernovae is relatively well understood, astronomers still do not know what happens when a core collapses to form a black hole. The discovery of 'under-energetic' gamma-ray bursts, like GRB 031203, should provide valuable clues as to links between supernovae, black holes and gamma-ray bursts. Lo-res JPG (22 Kb) Hi-res TIFF (5800 Kb) Cosmic gamma-ray bursts (GRBs) are flashes of gamma rays that can last from less than a second to a few minutes and occur at random positions in the sky. A large fraction of them is thought to result when a black hole is created from a dying star in a distant galaxy. Astronomers believe that a hot disc surrounding the black hole, made of gas and matter falling onto it, somehow emits an energetic beam parallel to the axis of rotation. According to the simplest picture, all GRBs should emit similar amounts of gamma-ray energy. The fraction of it detected at Earth should then depend on the 'width' (opening angle) and orientation of the beam as well as on the distance. The energy received should be larger when the beam is narrow or points towards us and smaller when the beam is broad or points away from us. New data collected with ESA's high energy observatories, Integral and XMM-Newton, now show that this picture is not so clear-cut and that the amount of energy emitted by GRBs can vary significantly. "The idea that all GRBs spit out the same amount of gamma rays, or that they are 'standard candles' as we call them, is simply ruled out by the new data," said Dr Sergey Sazonov, from the Space Research Institute of the Russian Academy of Sciences, Moscow (Russia) and the Max-Planck Institute for Astrophysics, Garching near Munich (Germany). Sazonov and an international team of researchers studied the GRB detected by Integral on 3 December 2003 and given the code-name of GRB 031203. Within a record 18 seconds of the burst, the Integral Burst Alert System had pinpointed the approximate position of GRB 031203 in the sky and sent the information to a network of observatories around the world. A few hours later one of them, ESA's XMM-Newton, determined a much more precise position for GRB 031203 and detected a rapidly fading X-ray source, which was subsequently seen by radio and optical telescopes on the ground. This wealth of data allowed astronomers to determine that GRB 031203 went off in a galaxy less than 1300 million light years away, making it the closest GRB ever observed. Even so, the way in which GRB 031203 dimmed with time and the distribution of its energy were not different from those of distant GRBs. Then, scientists started to realise that the concept of the 'standard candle' may not hold. "Being so close should make GRB 031203 appear very bright, but the amount of gamma-rays measured by Integral is about one thousand times less than what we would normally expect from a GRB," Sazonov said. A burst of gamma rays ob

2004-08-01

13

Cosmic Rays  

NSDL National Science Digital Library

This series of web pages gives an elementary discussion of cosmic rays, followed by sections on high energy particles in the universe and high-energy particles from the Sun. It describes the existence particles whose velocity approaches that of light, their probable sources, and their measurement. This is part of a large work, "The Exploration of the Earth's Magnetosphere", that gives a non-mathematical introduction to planetary and solar magnetic fields, space weather, aurora, and charged particle motion. A Spanish translation is available.

Stern, David

2005-04-27

14

Towards the installation and use of an extended array for cosmic ray detection: The EEE Project  

NASA Astrophysics Data System (ADS)

The Extreme Energy Events (EEE) project started to use an array of cosmic ray telescopes for muon detection, distributed over the italian territory. The use of such telescopes, based on Multigap Resistive Plate Chambers (MRPC) allows the study of the local muon flux, the detection of cosmic ray showers and the search for correlations between distant showers. The project is also intended to involve high school teams in an advanced research work. The present status of the installation and the first physics results are discussed here.

Abbrescia, M.; Alici, A.; An, S.; Antolini, R.; Badalà, A.; Baek, Y. W.; Baldini Ferroli, R.; Bencivenni, G.; Blanco, F.; Bressan, E.; Chiavassa, A.; Chiri, C.; Cicalò, C.; Cifarelli, L.; Coccia, E.; Coccetti, F.; de Caro, A.; de Gruttola, D.; de Pasquale, S.; D'Incecco, M.; Fabbri, F. L.; Frolov, V.; Garbini, M.; Guarnaccia, C.; Gustavino, C.; Hatzifotiadou, D.; Imponente, G.; Kim, J. S.; Kim, M. M.; La Rocca, P.; Librizzi, F.; Maggiora, A.; Menghetti, H.; Miozzi, S.; Moro, R.; Noferini, F.; Pagano, P.; Panareo, M.; Pappalardo, G. S.; Petta, C.; Piragino, G.; Preghenella, R.; Riggi, F.; Romano, F.; Russo, G.; Sartorelli, G.; Sbarra, C.; Scioli, G.; Selvi, M.; Serci, S.; Siddi, E.; Wenninger, H.; Williams, M. C. S.; Zampolli, C.; Zichichi, A.; Zuyeuski, R.

2009-05-01

15

Detection of cosmic gamma-rays using a heliostat field  

NASA Astrophysics Data System (ADS)

Gamma-Ray telescopes based on a solar plant are able to accurately measure the spatial distribution and time structure of the Cherenkov shower front. Although this information should be sufficient for the reconstruction of several primary parameters, it will be shown that the restricted field of view of the optical detection system and the limited sampling of a realistic heliostat array impose severe limitations.

Arqueros, F.; Ballestrin, J.; Borque, D. M.; Diaz Trigo, M.; Enriquez, R.; Gebauer, H.-J.; Plaga, R.

2001-08-01

16

Cosmic ray muon tomography system using drift chambers for the detection of Special Nuclear Materials  

Microsoft Academic Search

The smuggling of illicit Special Nuclear Materials (SNM) and Radiological Materials (RM) is a major security concern. Current radiation detection systems for cargo are not sensitive to well-shielded nuclear materials. The Muon Scattering Tomography (MST) method that we are developing might be a solution to this problem. It is based on the measurement of multiple scattering of cosmic ray-induced muons,

V. Anghel; J. Armitage; J. Botte; K. Boudjemline; D. Bryman; E. Charles; T. Cousins; A. Erlandson; G. Gallant; C. Jewett; G. Jonkmans; Z. Liu; S. Noel; G. Oakham; T. J. Stocki; M. Thompson; D. Waller

2010-01-01

17

Application of thermoluminescence for detection of cascade shower 2: Detection of cosmic ray cascade shower at Mount Fuji  

NASA Astrophysics Data System (ADS)

The results of a thermoluminescence (TL) chamber exposed at Mt. Fuji during Aug. '83 - Aug. '84 are reported. The TL signal induced by cosmic ray shower is detected and compared with the spot darkness of X-ray film exposed at the same time.

Akashi, M.; Kawaguchi, S.; Watanabe, Z.; Misaki, A.; Niwa, M.; Okamoto, Y.; Fujinaga, T.; Ichimura, M.; Shibata, T.; Dake, S.

1985-08-01

18

Application of thermoluminescence for detection of cascade shower 2: Detection of cosmic ray cascade shower at Mount Fuji  

Microsoft Academic Search

The results of a thermoluminescence (TL) chamber exposed at Mt. Fuji during Aug. '83 - Aug. '84 are reported. The TL signal induced by cosmic ray shower is detected and compared with the spot darkness of X-ray film exposed at the same time.

M. Akashi; S. Kawaguchi; Z. Watanabe; A. Misaki; M. Niwa; Y. Okamoto; T. Fujinaga; M. Ichimura; T. Shibata; S. Dake

1985-01-01

19

The detection of high charge cosmic ray nuclei  

Microsoft Academic Search

A large-area, light-weight electronic particle telescope was flown on a high altitude balloon in the summer of 1974 to study the heavy nuclei in the cosmic radiation. This telescope consisted of a double Cerenkov-double scintillator array composed of four 1.22 m diameter disk radiators mounted in light diffusion boxes, each looked at by multiple photomultipliers. The impact point of each

W. R. Scarlett; P. S. Freier; C. J. Waddington

1975-01-01

20

Detection of Point Sources in Cosmic Ray Maps Using the Mexican Hat Wavelet Family  

NASA Astrophysics Data System (ADS)

An analysis of the sensitivity of gaussian and mexican hat wavelet family filters to the detection of point sources of ultra-high energy cosmic rays was performed. A source embedded in a background was simulated and the number of events and amplitude of this source was varied aiming to check the sensitivity of the method to detect faint sources with low statistic of events.

Alves Batista, Rafael; Kemp, Ernesto; Daniel, Bruno

21

X-ray Emissions Detected From Elusive Cosmic Objects  

NASA Astrophysics Data System (ADS)

A type of celestial object that has long stumped astronomers has been found to emit X-rays, thus proving a theory of how the objects form. Dr. Steven Pravdo of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and other scientists have concluded that these objects, called Herbig Haro objects, are produced by high velocity shocks. Pravdo is the lead author of a paper published in the Oct. 18 issue of the journal Nature. Herbig Haro objects are found in regions where new stars are forming. They are nebulas, or dust and gas clouds. They form when high-velocity gas emitted from young stars collides with clouds of interstellar material. The collision heats the gas in the surrounding nebula to sufficiently high temperatures to produce X-rays. Observations for the past 20 years showed no evidence of X-ray emission from these objects, which are named for astronomers George Herbig and Guillermo Haro. Previous instruments lacked the resolution and sensitivity necessary to 'see' these X-rays. The discovery of the X-ray emissions was possible through the very powerful Advanced CCD Imaging Spectrometer on NASA's Chandra X-ray Observatory, which has been in orbit since 1999. On Oct. 8, 2000, astrophysicists used the instrument to study HH2, one of the brightest and closest Herbig Haro objects in the Orion Nebula. They determined that HH2 contains shock-heated material with a temperature of about 1 million degrees Kelvin. Pravdo and his team used three criteria to rule out the possibility that the emissions came from any other source. First, Chandra's high spatial resolution pinpointed the location of the X-rays at HH2. Second, the X-rays appeared to be covering a region bigger than a star. Third, the temperature of the X-rays was about 1 million degrees, cooler than nearby X-ray stars. One million degrees is about the temperature expected if material moving at about 300 kilometers per second (about 600,000 miles per hour) collides. At this speed, you could go from Los Angeles to San Diego and back in one second. The principal investigator of the Advanced CCD Imaging Spectrometer, Dr. Gordon Garmire of Pennsylvania State University, University Park, is a co-author of the paper. Other co-authors include Drs. Yohko Tsuboi, Yoshitomo Maeda and Eric Feigelson, all from Pennsylvania State University, and Dr. John Bally from the University of Colorado, Boulder. The Advanced CCD Imaging Spectrometer X-ray camera was developed for NASA by Pennsylvania State University and the Massachusetts Institute of Technology, Cambridge, Mass. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program. TRW, Inc., Redondo Beach, Calif., is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, Mass. Images associated with this release are available on the World Wide Web at: http://chandra.harvard.edu AND http://chandra.nasa.gov The Chandra X-ray Observatory is managed for NASA by the Smithsonian Astrophysical Observatory, Cambridge, Mass. JPL is managed for NASA by the California Institute of Technology in Pasadena.

2001-10-01

22

Detection and imaging of atmospheric radio flashes from cosmic ray air showers.  

PubMed

The nature of ultrahigh-energy cosmic rays (UHECRs) at energies >10(20) eV remains a mystery. They are likely to be of extragalactic origin, but should be absorbed within approximately 50 Mpc through interactions with the cosmic microwave background. As there are no sufficiently powerful accelerators within this distance from the Galaxy, explanations for UHECRs range from unusual astrophysical sources to exotic string physics. Also unclear is whether UHECRs consist of protons, heavy nuclei, neutrinos or gamma-rays. To resolve these questions, larger detectors with higher duty cycles and which combine multiple detection techniques are needed. Radio emission from UHECRs, on the other hand, is unaffected by attenuation, has a high duty cycle, gives calorimetric measurements and provides high directional accuracy. Here we report the detection of radio flashes from cosmic-ray air showers using low-cost digital radio receivers. We show that the radiation can be understood in terms of the geosynchrotron effect. Our results show that it should be possible to determine the nature and composition of UHECRs with combined radio and particle detectors, and to detect the ultrahigh-energy neutrinos expected from flavour mixing. PMID:15902250

Falcke, H; Apel, W D; Badea, A F; Bähren, L; Bekk, K; Bercuci, A; Bertaina, M; Biermann, P L; Blümer, J; Bozdog, H; Brancus, I M; Buitink, S; Brüggemann, M; Buchholz, P; Butcher, H; Chiavassa, A; Daumiller, K; de Bruyn, A G; de Vos, C M; Di Pierro, F; Doll, P; Engel, R; Gemmeke, H; Ghia, P L; Glasstetter, R; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Huege, T; Kampert, K-H; Kant, G W; Klein, U; Kolotaev, Y; Koopman, Y; Krömer, O; Kuijpers, J; Lafebre, S; Maier, G; Mathes, H J; Mayer, H J; Milke, J; Mitrica, B; Morello, C; Navarra, G; Nehls, S; Nigl, A; Obenland, R; Oehlschläger, J; Ostapchenko, S; Over, S; Pepping, H J; Petcu, M; Petrovic, J; Plewnia, S; Rebel, H; Risse, A; Roth, M; Schieler, H; Schoonderbeek, G; Sima, O; Stümpert, M; Toma, G; Trinchero, G C; Ulrich, H; Valchierotti, S; van Buren, J; van Cappellen, W; Walkowiak, W; Weindl, A; Wijnholds, S; Wochele, J; Zabierowski, J; Zensus, J A; Zimmermann, D

2005-05-19

23

Cosmic x ray physics  

NASA Technical Reports Server (NTRS)

The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1991-01-01

24

Cosmic x ray physics  

NASA Technical Reports Server (NTRS)

The annual progress report on Cosmic X Ray Physics is presented. Topics studied include: the soft x ray background, proportional counter and filter calibrations, the new sounding rocket payload: X Ray Calorimeter, and theoretical studies.

Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1990-01-01

25

Geometrical reconstruction of UHE cosmic rays detected by fluorescent detectors  

NASA Astrophysics Data System (ADS)

We present the geometrical reconstruction of the events detected by fluorescence detectors (FD) similar to those of the Pierre Auger Observatory (PAO). The input of the geometrical reconstruction program is given by the output data of the FD simulation program, FD_sim. The efficiency of this program is computed by comparing its results with the data of the simulated shower. The implementation of the hybrid reconstruction is also discussed.

Díaz, J. C.; Shellard, R. C.; Amaral, M. G.

2001-04-01

26

Cosmic Rays in Thunderstorms  

NASA Astrophysics Data System (ADS)

Cosmic Rays in Thunderstorms Cosmic rays are protons and heavier nuclei that constantly bombard the Earth's atmosphere with energies spanning a vast range from 109 to 1021 eV. At typical altitudes up to 10-20 km they initiate large particle cascades, called extensive air showers, that contain millions to billions of secondary particles depending on their initial energy. These particles include electrons, positrons, hadrons and muons, and are concentrated in a compact particle front that propagates at relativistic speed. In addition, the shower leaves behind a trail of lower energy electrons from ionization of air molecules. Under thunderstorm conditions these electrons contribute to the electrical and ionization processes in the cloud. When the local electric field is strong enough the secondary electrons can create relativistic electron run-away avalanches [1] or even non-relativistic avalanches. Cosmic rays could even trigger lightning inception. Conversely, strong electric fields also influence the development of the air shower [2]. Extensive air showers emit a short (tens of nanoseconds) radio pulse due to deflection of the shower particles in the Earth's magnetic field [3]. Antenna arrays, such as AERA, LOFAR and LOPES detect these pulses in a frequency window of roughly 10-100 MHz. These systems are also sensitive to the radiation from discharges associated to thunderstorms, and provide a means to study the interaction of cosmic ray air showers and the electrical processes in thunderstorms [4]. In this presentation we discuss the involved radiation mechanisms and present analyses of thunderstorm data from air shower arrays [1] A. Gurevich et al., Phys. Lett. A 165, 463 (1992) [2] S. Buitink et al., Astropart. Phys. 33, 1 (2010) [3] H. Falcke et al., Nature 435, 313 (2005) [4] S. Buitink et al., Astron. & Astrophys. 467, 385 (2007)

Buitink, Stijn; Scholten, Olaf; van den Berg, Ad; Ebert, Ute

2013-04-01

27

How Cosmic Rays Affect Humans  

NSDL National Science Digital Library

In this lesson about cosmic rays, students will describe why cosmic rays are dangerous to astronauts. Includes information about student preconceptions. This is activity 3 of 4 from "The Cosmic Ray Telescope for the Effects of Radiation (CRaTER)."

28

New detection technologies for ultra-high energy cosmic rays and neutrinos  

NASA Astrophysics Data System (ADS)

Even with an accumulated data set from an integrated six years of lifetime from the Auger experiment, no point sources of charged cosmic rays have be identified at the highest energies. Significantly increased apertures such as promised by the JEMEUSO mission will be required to identify these sources from the cosmic ray signatures themselves. However, in employing water-cherenkov surface detectors as well as fluorescence telescopes, Auger has demonstrated the power provided by the hybrid technology approach. New detection technologies thus provide a valuable tool, in particular for the study of systematic effects. Over the past decade, in particular radio detection of cosmic ray air-showers has become a viable future detection technology to enhance and complement existing air-shower experiments. Following the proof-of-principle provided by the Lopes experiment, this technology is now being pursued in all major air-shower detectors. In the MHz regime, the radio signal is dominated by geomagnetic emission from the electrons deflected in the earth magnetic field, with secondary contributions from a global charge excess. As the majority of the energy in the shower is carried by these electron and the radio signal traverses the atmosphere basically unattenuated, this approach not only promises superior energy resolution but may also provide an independent handle on the longitudinal shower development and hence the primary composition. Theoretical signal predictions provided by detailed Monte-Carlo simulations as well as analytic shower parametrizations are in good agreement with measurements provided by the AERA and Codalema experiments. Recent efforts also include studies of the radio emission in the GHz regime, where the ambient noise is significantly reduced, yet the emission mechanism in this regime has not been firmly established yet. As neutrinos are not deflected in the intergalactic magnetic fields, the detection of neutrino-induced cascades in dense media provides another promising approachfor the identification of the sources of cosmic rays. The low event rates and large required target volumes limit the experimental methods to far-ranging signatures .from the cascade, such as acoustic emission from the quasi-instantaneous energy deposit or Cherenkov emission from the charged particles in the cascade. Searching for optical Cherenkov photons in a cubic-kilometer of Antarctic ice, the IceCube experiment has recently found an excess of high-energy neutrinos in the TeV-PeV range.Yet its effective volume is too small to detect the GZK flux predicted from interaction of the highest-energy cosmic rays with the ambient cosmic microwave background. Seeking to increase the observed target volume, radio observations of the rim of the moon have energy thresholds well beyond the EeV scale and thus are more likely to find interactions of charged cosmic rays than GZK neutrinos. The currently best sensitivity to this flux is provided from searches for GHz radio emission of neutrino-induced cascades in the antarctic ice from the ANITA ballon experiment. While no high-energy neutrinos have been found, a geomagnetic emission component from air-showers

Böser, Sebastian

2013-06-01

29

Aerial Neutron Detection of Cosmic-Ray Interactions with the Earth's Surface  

SciTech Connect

We have demonstrated the ability to measure the neutron flux produced by the cosmic-ray interaction with nuclei in the ground surface using aerial neutron detection. High energy cosmic-rays (primarily muons with GeV energies) interact with the nuclei in the ground surface and produce energetic neutrons via spallation. At the air-surface interface, the neutrons produced by spallation will either scatter within the surface material, become thermalized and reabsorbed, or be emitted into the air. The mean free path of energetic neutrons in air can be hundreds of feet as opposed to a few feet in dense materials. As such, the flux of neutrons escaping into the air provides a measure of the surface nuclei composition. It has been demonstrated that this effect can be measured at long range using neutron detectors on low flying helicopters. Radiological survey measurements conducted at Government Wash in Las Vegas, Nevada, have shown that the neutron background from the cosmic-soil interactions is repeatable and directly correlated to the geological data. Government Wash has a very unique geology, spanning a wide variety of nuclide mixtures and formations. The results of the preliminary measurements are presented.

Richard Maurer

2008-09-18

30

The Extragalactic Background Light and the Detection of the Cosmic Gamma-Ray Horizon  

NASA Astrophysics Data System (ADS)

The first statistically significant detection of the cosmic gamma-ray horizon (CGRH) that is independent of any extragalactic background light (EBL) model is presented in this talk. The CGRH is a fundamental quantity in cosmology. It gives an estimate of the opacity of the Universe to very-high energy (VHE) gamma-ray photons due to photon-photon pair production with the EBL. The only estimations of the CGRH to date are predictions from EBL models and lower limits from gamma-ray observations of cosmological blazars and gamma-ray bursts. Here, we present synchrotron/synchrotron self-Compton models (SSC) of the spectral energy distribution of 15 blazars based on (almost) simultaneous observations from radio up to the highest energy gamma-rays taken with the Fermi satellite. These synchrotron/SSC models predict the unattenuated VHE fluxes, which are compared with the observations by imaging atmospheric Cherenkov telescopes. This comparison provides an estimation of the optical depth of the EBL, which allows a derivation of the CGRH through a Monte Carlo analysis that is EBL-model independent. We find that the observed CGRH is compatible with the current knowledge of the EBL. We conclude showing that the detection of the CGRH allows us to estimate the expansion rate of the Universe from gamma-ray attenuation.

Finke, Justin; Dominguez, A.; Primack, J. R.; Prada, F.; Kitaura, F.; Siana, B. D.; Fermi-LAT Collaboration

2014-01-01

31

Latest results of the CODALEMA experiment: cosmic rays radio detection in a self trigger mode  

NASA Astrophysics Data System (ADS)

Dedicated to the measurement of the radio transients coming from the extensive air showers (EAS), the CODALEMA experiment was started in 2001 at the Nançay Observatory, in France. Benefiting of an easy deployment and a low cost compared with Cherenkov detectors or fluorescence telescopes, this alternative method appears to be an interesting tool for the understanding of the physics of high energy cosmic rays observed through EAS. A new configuration of the CODALEMA experiment was implemented in 2011 based on a standalone detection, which will be essential for the next generation of giant detector array. One of the major challenges of this promising detection mode is the control (identification and rejection) of the fluctuating and transient noise events in an inhabited area and the knowledge of the shower radio-detection capabilities such as the effective efficiency and the data purity. Some results concerning this new setup of the experiment will be discussed in this paper.

Torres Machado, Diego; CODALEMA Collaboration

2013-02-01

32

Detecting filaments in the ultra-high energy cosmic ray distribution  

NASA Astrophysics Data System (ADS)

We propose and test new statistical tools to study the distribution of cosmic rays based on the use of the minimal spanning tree. The method described is particularly sensitive to filamentary structures, as those expected to arise from strong sources of charged cosmic rays which get deflected by intervening magnetic fields. We also test the method with data available from the AGASA and SUGAR surface detector arrays.

Harari, Diego; Mollerach, Silvia; Roulet, Esteban

2006-07-01

33

Detection of the Cosmic ?-Ray Horizon from Multiwavelength Observations of Blazars  

NASA Astrophysics Data System (ADS)

The first statistically significant detection of the cosmic ?-ray horizon (CGRH) that is independent of any extragalactic background light (EBL) model is presented. The CGRH is a fundamental quantity in cosmology. It gives an estimate of the opacity of the universe to very high energy (VHE) ?-ray photons due to photon-photon pair production with the EBL. The only estimations of the CGRH to date are predictions from EBL models and lower limits from ?-ray observations of cosmological blazars and ?-ray bursts. Here, we present homogeneous synchrotron/synchrotron self-Compton (SSC) models of the spectral energy distributions of 15 blazars based on (almost) simultaneous observations from radio up to the highest energy ?-rays taken with the Fermi satellite. These synchrotron/SSC models predict the unattenuated VHE fluxes, which are compared with the observations by imaging atmospheric Cherenkov telescopes. This comparison provides an estimate of the optical depth of the EBL, which allows us a derivation of the CGRH through a maximum likelihood analysis that is EBL-model independent. We find that the observed CGRH is compatible with the current knowledge of the EBL.

Domínguez, A.; Finke, J. D.; Prada, F.; Primack, J. R.; Kitaura, F. S.; Siana, B.; Paneque, D.

2013-06-01

34

DETECTION OF THE COSMIC {gamma}-RAY HORIZON FROM MULTIWAVELENGTH OBSERVATIONS OF BLAZARS  

SciTech Connect

The first statistically significant detection of the cosmic {gamma}-ray horizon (CGRH) that is independent of any extragalactic background light (EBL) model is presented. The CGRH is a fundamental quantity in cosmology. It gives an estimate of the opacity of the universe to very high energy (VHE) {gamma}-ray photons due to photon-photon pair production with the EBL. The only estimations of the CGRH to date are predictions from EBL models and lower limits from {gamma}-ray observations of cosmological blazars and {gamma}-ray bursts. Here, we present homogeneous synchrotron/synchrotron self-Compton (SSC) models of the spectral energy distributions of 15 blazars based on (almost) simultaneous observations from radio up to the highest energy {gamma}-rays taken with the Fermi satellite. These synchrotron/SSC models predict the unattenuated VHE fluxes, which are compared with the observations by imaging atmospheric Cherenkov telescopes. This comparison provides an estimate of the optical depth of the EBL, which allows us a derivation of the CGRH through a maximum likelihood analysis that is EBL-model independent. We find that the observed CGRH is compatible with the current knowledge of the EBL.

Dominguez, A.; Siana, B. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Finke, J. D. [U.S. Naval Research Laboratory, Space Science Division, Code 7653, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Prada, F. [Campus of International Excellence UAM-CSIC, Cantoblanco, E-28049 Madrid (Spain); Primack, J. R. [Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Kitaura, F. S. [Leibniz-Institut fuer Astrophysik (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Paneque, D., E-mail: albertod@ucr.edu [Kavli Institute for Particle Astrophysics and Cosmology, SLAC, Stanford University, Stanford, CA 94305 (United States)

2013-06-10

35

Cosmic Ray Dosimetry  

NASA Astrophysics Data System (ADS)

Radiation levels at aircraft cruising altitudes are twenty times higher than at sea level. Thus, on average, a typical airline pilot receives a larger annual radiation dose than some one working in nuclear industry. The main source of this radiation is from galactic cosmic radiation, high energy particles generated by exploding stars within our own galaxy. In this work we study cosmic rays dosimetry at various aviation altitudes using the PARMA model.

Si Belkhir, F.; Attallah, R.

2010-10-01

36

Ionisation as indicator for cosmic ray acceleration  

NASA Astrophysics Data System (ADS)

Astrospheres and wind bubbles of massive stars are believed to be sources of cosmic rays with energies E ≲ 1 TeV. These particles are not directly detectable, but their impact on surrounding matter, in particular ionisation of atomic and molecular hydrogen, can lead to observable signatures. A correlation study of both gamma ray emission, induced by proton-proton interactions of cosmic ray protons with kinetic energies Ep ? 280 MeV with ambient hydrogen, and ionisation induced by cosmic ray protons of kinetic energies Ep < 280 MeV can be performed in order to study potential sources of (sub)TeV cosmic rays.

Schuppan, F.; Röken, C.; Fedrau, N.; Becker Tjus, J.

2014-06-01

37

Scintillator Cosmic Ray Super Telescope  

NASA Astrophysics Data System (ADS)

The Scintillator Cosmic Ray Super Telescope (SciCRST) is a new experiment to detect solar neutrons, and also it is expected to work as a muon and cosmic ray detector. The SciCRST consist of 14,848 plastic scintillator bars, and it will be installed at the top of Sierra Negra volcano, Mexico, 4580 m.a.s.l. We use a prototype, called as miniSciBar, to test the hardware and software of the final experiment. In this paper, we present the status and details of the experiment, and results of the prototype.

González, L. X.; Valdés-Galicia, J. F.; Matsubara, Y.; Nagai, Y.; Itow, Y.; Sako, T.; López, D.; Mitsuka, G.; Munakata, K.; Kato, C.; Yasue, S.; Kosai, M.; Tsurusashi, M.; Nakamo, Y.; Shibata, S.; Takamaru, H.; Kojima, H.; Tsuchiya, H.; Watanabe, K.; Koi, T.; Fragoso, E.; Hurtado, A.; Musalem, O.

2013-04-01

38

Radio emission from extensive air showers as a method for cosmic-ray detection  

NASA Astrophysics Data System (ADS)

At the present time, radio emission from extensive air showers (EASs) is being considered as a new promising method for detecting cosmic rays of energy in the region E 0 > 5 × 1016 eV. Radio emission from an EAS whose development is simulated by the Monte Carlo method is calculated here. The field of radio emission from an EAS is calculated on the basis of two representations of a shower: that as a set of individual particles and that as a continuous set of currents. The sensitivity of radio emission to EAS parameters in the frequency range 10-100 MHz is investigated. The results can be used to analyze experiments that being presently performed (CODALEMA and LOPES) and those that are being planned for the future.

Kalmykov, N. N.; Konstantinov, A. A.; Engel, R.

2010-07-01

39

A Cocoon of Freshly Accelerated Cosmic Rays Detected by Fermi in the Cygnus Superbubble  

NASA Astrophysics Data System (ADS)

The origin of Galactic cosmic rays is a century-long puzzle. Indirect evidence points to their acceleration by supernova shockwaves, but we know little of their escape from the shock and their evolution through the turbulent medium surrounding massive stars. Gamma rays can probe their spreading through the ambient gas and radiation fields. The Fermi Large Area Telescope (LAT) has observed the star-forming region of Cygnus X. The 1- to 100-gigaelectronvolt images reveal a 50-parsec-wide cocoon of freshly accelerated cosmic rays that flood the cavities carved by the stellar winds and ionization fronts from young stellar clusters. It provides an example to study the youth of cosmic rays in a superbubble environment before they merge into the older Galactic population.

Ackermann, M.; Ajello, M.; Allafort, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Belfiore, A.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bottacini, E.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cecchi, C.; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; de Angelis, A.; de Palma, F.; Dermer, C. D.; do Couto e Silva, E.; Drell, P. S.; Dumora, D.; Favuzzi, C.; Fegan, S. J.; Focke, W. B.; Fortin, P.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Germani, S.; Giglietto, N.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Guillemot, L.; Guiriec, S.; Hadasch, D.; Hanabata, Y.; Harding, A. K.; Hayashida, M.; Hayashi, K.; Hays, E.; Jóhannesson, G.; Johnson, A. S.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kerr, M.; Knödlseder, J.; Kuss, M.; Lande, J.; Latronico, L.; Lee, S.-H.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Martin, P.; Mazziotta, M. N.; McEnery, J. E.; Mehault, J.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Naumann-Godo, M.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Okumura, A.; Orlando, E.; Ormes, J. F.; Ozaki, M.; Paneque, D.; Parent, D.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Pohl, M.; Prokhorov, D.; Rainò, S.; Rando, R.; Razzano, M.; Reposeur, T.; Ritz, S.; Parkinson, P. M. Saz; Sgrò, C.; Siskind, E. J.; Smith, P. D.; Spinelli, P.; Strong, A. W.; Takahashi, H.; Tanaka, T.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Torres, D. F.; Tosti, G.; Tramacere, A.; Troja, E.; Uchiyama, Y.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.; Waite, A. P.; Wang, P.; Winer, B. L.; Wood, K. S.; Yang, Z.; Zimmer, S.; Bontemps, S.

2011-11-01

40

A cocoon of freshly accelerated cosmic rays detected by Fermi in the Cygnus superbubble.  

PubMed

The origin of Galactic cosmic rays is a century-long puzzle. Indirect evidence points to their acceleration by supernova shockwaves, but we know little of their escape from the shock and their evolution through the turbulent medium surrounding massive stars. Gamma rays can probe their spreading through the ambient gas and radiation fields. The Fermi Large Area Telescope (LAT) has observed the star-forming region of Cygnus X. The 1- to 100-gigaelectronvolt images reveal a 50-parsec-wide cocoon of freshly accelerated cosmic rays that flood the cavities carved by the stellar winds and ionization fronts from young stellar clusters. It provides an example to study the youth of cosmic rays in a superbubble environment before they merge into the older Galactic population. PMID:22116880

Ackermann, M; Ajello, M; Allafort, A; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Belfiore, A; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bottacini, E; Brigida, M; Bruel, P; Buehler, R; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cecchi, C; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; de Angelis, A; de Palma, F; Dermer, C D; do Couto E Silva, E; Drell, P S; Dumora, D; Favuzzi, C; Fegan, S J; Focke, W B; Fortin, P; Fukazawa, Y; Fusco, P; Gargano, F; Germani, S; Giglietto, N; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, I A; Guillemot, L; Guiriec, S; Hadasch, D; Hanabata, Y; Harding, A K; Hayashida, M; Hayashi, K; Hays, E; Jóhannesson, G; Johnson, A S; Kamae, T; Katagiri, H; Kataoka, J; Kerr, M; Knödlseder, J; Kuss, M; Lande, J; Latronico, L; Lee, S-H; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Martin, P; Mazziotta, M N; McEnery, J E; Mehault, J; Michelson, P F; Mitthumsiri, W; Mizuno, T; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Naumann-Godo, M; Nolan, P L; Norris, J P; Nuss, E; Ohsugi, T; Okumura, A; Orlando, E; Ormes, J F; Ozaki, M; Paneque, D; Parent, D; Pesce-Rollins, M; Pierbattista, M; Piron, F; Pohl, M; Prokhorov, D; Rainò, S; Rando, R; Razzano, M; Reposeur, T; Ritz, S; Parkinson, P M Saz; Sgrò, C; Siskind, E J; Smith, P D; Spinelli, P; Strong, A W; Takahashi, H; Tanaka, T; Thayer, J G; Thayer, J B; Thompson, D J; Tibaldo, L; Torres, D F; Tosti, G; Tramacere, A; Troja, E; Uchiyama, Y; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Waite, A P; Wang, P; Winer, B L; Wood, K S; Yang, Z; Zimmer, S; Bontemps, S

2011-11-25

41

Development of a two-fold segmented detection system for near horizontally cosmic-ray muons to probe the internal structure of a volcano  

Microsoft Academic Search

Very high-energy cosmic-ray muons penetrating through a mountain enable us to probe internal structure of volcanoes. An improved cosmic-ray muon detection system comprising two segmented detectors with multiplicity cut of the soft-component background of cosmic ray was developed. By applying to the measurement on internal structure of the volcano Mt. Asama, we proved that the volume occupancy in the region

H. Tanaka; K. Nagamine; N. Kawamura; S. N. Nakamura; K. Ishida; K. Shimomura

2003-01-01

42

On the Possibility of Radar Detection of Ultra-high Energy Cosmic Ray- and Neutrino-induced Air Showers  

NASA Technical Reports Server (NTRS)

We show that cosmic rays air showers resulting from primaries with energies above 10(sup 19) eV should be straightforward to detect with radar ranging techniques, where the radar echoes are produced by scattering from the column of ionized air produced by the shower.

Gorham, P.

1999-01-01

43

Determining Muon Detection Efficiency Rates of Limited Streamer Tube Modules using Cosmic Ray Detector  

SciTech Connect

In the Babar detector at the Stanford Linear Accelerator Center, the existing muon detector system in the Instrumented Flux Return gaps is currently being upgraded. Limited Streamer Tubes (LST) have been successful in other projects in the past, and are thus reliable and sensible detectors to use. The tubes have been assembled into modules to strengthen the mechanical structure [2]. Before installation, numerous tests must be performed on the LST modules to ensure that they are in good condition. One important check is to determine the muon detection efficiency rates of the modules. In this study, a cosmic ray detector was built to measure the efficiency rates of the LST modules. Five modules themselves were used as muon triggers. Two z strip planes were also constructed as part of the setup. Singles rate measurements were done on the five modules to ensure that high voltage could be safely applied to the LST. Particle count vs. voltage graphs were generated, and most of the graphs plateau normally. Wire signals from the LST modules as well as induced signals from the strip planes were used to determine the x-y-z coordinates of the muon hits in a stack of modules. Knowing the geometry of the stack, a plot of the potential muon path was generated. Preliminary results on muon detection efficiency rates of the modules in one stack are presented here. Efficiencies of the modules were determined to be between 80% and 90%, but there were large statistical errors (7%) due to the limited time available for cosmic data runs. More data samples will be taken soon; they will hopefully provide more precise measurements, with 1-2% errors for most modules before installation. Future work includes systematic studies of muon detection efficiency as a function of the operating voltage and threshold voltage settings.

Pan, M.

2004-09-03

44

Educational Cosmic Ray Arrays  

SciTech Connect

In the last decade a great deal of interest has arisen in using sparse arrays of cosmic ray detectors located at schools as a means of doing both outreach and physics research. This approach has the unique advantage of involving grade school students in an actual ongoing experiment, rather then a simple teaching exercise, while at the same time providing researchers with the basic infrastructure for installation of cosmic ray detectors. A survey is made of projects in North America and Europe and in particular the ALTA experiment at the University of Alberta which was the first experiment operating under this paradigm.

Soluk, R. A. [Centre for Subatomic Research, University of Alberta, Edmonton, Alberta, T6G 2N5 (Canada)

2006-04-11

45

Future use of silicon photomultipliers for the fluorescence detection of ultra-high-energy cosmic rays  

NASA Astrophysics Data System (ADS)

A sophisticated technique to measure extensive air showers initiated by ultra-high-energy cosmic rays is by means of fluorescence telescopes. Secondary particles of the air shower excite nitrogen molecules of the atmosphere, which emit fluorescence light when they de-excite. Due to their high photon detection efficiency (PDE) silicon photomultipliers (SiPMs) promise to increase the sensitivity of todays fluorescence telescopes which use photomultiplier tubes - for example the fluorescence detector of the Pierre Auger Observatory. On the other hand drawbacks like a small sensitive area, a strong temperature dependency and a high noise rate have to be managed. We present plans for a prototype fluorescence telescope using SiPMs and a special light collecting optical system of Winston cones to increase the sensitive area. In this context we made measurements of the relative PDE of SiPMs depending on the incident angle of light. The results agree with calculations based on the Fresnel equations. Furthermore, measurements of the brightness of the night sky are presented since this photon flux is the main background to the fluorescence signals of the extensive air showers. To compensate the temperature dependency of the SiPM, frontend electronics make use of temperature sensors and microcontrollers to directly adjust the bias-voltage according to the thermal conditions. To reduce the noise rate we study the coincidence of several SiPMs signals triggered by cosmic ray events. By summing up these signals the SiPMs will constitute a single pixel of the fluorescence telescope.

Stephan, Maurice; Hebbeker, Thomas; Lauscher, Markus; Meurer, Christine; Niggemann, Tim; Schumacher, Johannes

2011-09-01

46

Discovery of cosmic rays  

NASA Astrophysics Data System (ADS)

The mysterious invisible radiation that ionized air was studied a century ago by many scientists. Finally, on 7 August 1912, Victor Hess in his seventh balloon flight that year, reached an altitude of about 5000 m. With his electroscopes on board the hydrogen-filled balloon he observed that the ionization instead of decreasing with altitude increased significantly. Hess had discovered cosmic rays, a discovery that gave him the 1936 Nobel Prize in physics. When research resumed after World War I focus was on understanding the nature of the cosmic radiation. Particles or radiation? Positive or negative? Electrons, positrons or protons? Progress came using new instruments like the Geiger-Muller tube and around 1940 it was clear that cosmic rays were mostly protons.

Carlson, Per

2013-02-01

47

Investigating cosmic ray coincidences  

NASA Astrophysics Data System (ADS)

Every laboratory has its own supply of high energy particles. Secondary cosmic rays provide a sea level flux of muons at a rate of about 1 cm-2 min-1. This article describes an extracurricular A-level investigation that indicates muon-electron collisions in the roof of the laboratory.

Dunne, Peter; Miller, Alex

2001-07-01

48

The cosmic triad: Cosmic rays, gamma-rays and neutrinos  

NASA Astrophysics Data System (ADS)

The existence of ultra-high energy (UHE) cosmic rays (CRs) with energies up to 100 EeV is a strong motivation for neutrino astronomy at the EeV energy scale. It seems unavoidable that UHE CRs undergo hadronic interactions with radiation backgrounds and ambient matter prior to their arrival at Earth. These interactions result in a flux of secondary neutrinos and ?-rays with energies up to a few percent of the initial CR energy. So far, no high-energy neutrino source could be unambiguously identified. We will review the various indirect neutrino limits that arise from the cosmic connection of UHE CRs, ?-rays and neutrinos. At the EeV energy scale the diffuse flux of cosmogenic neutrinos associated with the propagation of ultra-high energy cosmic rays in the cosmic radiation background seems to be the most promising candidate for a future detection. We will discuss its model dependence w.r.t. nuclear composition and evolution of the sources.

Ahlers, Markus

2013-05-01

49

Overview of radio detection of cosmic ray air showers in the MHz range, and prospects for a large scale experiment  

NASA Astrophysics Data System (ADS)

Since its revival in the last decade, radio detection of cosmic ray air showers has made tremendous progress. Today, several experiments are routinely detecting radio signals associated with air showers. Large cosmic ray observatories such as the Pierre Auger Observatory are also pursuing radio detection activities. As an introduction, in this article we will summarize the main results from the first generation of radio detection experiments: LOPES and CODALEMA. Then, we will show which questions concerning the radio emission mechanisms can be answered from larger-scale experiments like the Auger Engineering Radio Array (AERA), which is a 20 km2 antenna array under construction close to other enhancement devices at the Pierre Auger Observatory.

Melissas, Maximilien; Pierre Auger Collaboration

2011-06-01

50

Direction identification in radio images of cosmic-ray air showers detected with LOPES and KASCADE  

Microsoft Academic Search

Aims: We want to understand the emission mechanism of radio emission from air showers to determine the origin of high-energy cosmic rays. Therefore, we study the geometry of the air shower radio emission measured with LOPES and search for systematic effects between the direction determined on the radio signal and the direction provided by the particle detector array KASCADE. Methods:

A. Nigl; W. D. Apel; J. C. Arteaga; T. Asch; J. Auffenberg; F. Badea; L. Bähren; K. Bekk; M. Bertaina; P. L. Biermann; J. Blümer; H. Bozdog; I. M. Brancus; M. Brüggemann; P. Buchholz; S. Buitink; H. Butcher; E. Cantoni; A. Chiavassa; F. Cossavella; K. Daumiller; V. de Souza; F. di Pierro; P. Doll; R. Engel; H. D. E. Falcke; H. Gemmeke; P. L. Ghia; R. Glasstetter; C. Grupen; A. Haungs; D. Heck; J. R. Hörandel; A. Horneffer; T. Huege; P. G. Isar; K.-H. Kampert; D. Kickelbick; Y. Kolotaev; O. Krömer; J. Kuijpers; S. J. Lafèbre; P. Luczak; M. Manewald; H. J. Mathes; H. J. Mayer; C. Meurer; B. Mitrica; C. Morello; G. Navarra; S. Nehls; J. Oehlschläger; S. Ostapchenko; S. Over; M. Petcu; T. Pierog; J. Rautenberg; H. Rebel; M. Roth; A. Saftoiu; H. Schieler; A. Schmidt; F. Schröder; O. Sima; K. Singh; M. Stümpert; G. Toma; G. C. Trinchero; H. Ulrich; J. van Buren; W. Walkowiak; A. Weindl; J. Wochele; J. Zabierowski; J. A. Zensus

2008-01-01

51

COSMIC-RAY MUON TOMOGRAPHY AND ITS APPLICATION TO THE DETECTION OF HIGH-Z MATERIALS  

Microsoft Academic Search

Each minute, about 10000 muons rain down on every square meter of Earth. These charged elementary particles are produced by cosmic rays striking the upper atmosphere. Millions of highly penetrative muons pass through our bodies, cars and houses daily. Penetrating the objects, muons interact with atoms of different materials, mainly electromagnetically. They are more strongly deflected, or scattered, by high-Z

Konstantin Borozdin; Thomas Asaki; Rick Chartrand; Mark Galassi; Andrew Greene

52

A Bayesian analysis of the 27 highest energy cosmic rays detected by the Pierre Auger Observatory  

NASA Astrophysics Data System (ADS)

It is possible that ultrahigh energy cosmic rays (UHECRs) are generated by active galactic nuclei (AGNs), but there is currently no conclusive evidence for this hypothesis. Several reports of correlations between the arrival directions of UHECRs and the positions of nearby AGNs have been made, the strongest detection coming from a sample of 27 UHECRs detected by the Pierre Auger Observatory (PAO). However, the PAO results were based on a statistical methodology that not only ignored some relevant information (most obviously the UHECR arrival energies, but also some of the information in the arrival directions), but also involved some problematic fine-tuning of the correlation parameters. Here we present a fully Bayesian analysis of the PAO data (collected before 2007 September), which makes use of more of the available information, and find that a fraction FAGN= 0.15+0.10-0.07 of the UHECRs originate from known AGNs in the Veron-Cetty and Veron (VCV) catalogue. The hypothesis that all the UHECRs come from VCV AGNs is ruled out, although there remains a small possibility that the PAO-AGN correlation is coincidental (FAGN= 0.15 is 200 times as probable as FAGN= 0.00).

Watson, Laura J.; Mortlock, Daniel J.; Jaffe, Andrew H.

2011-11-01

53

Detection of High Energy Cosmic Ray with the Advanced Thin Ionization Calorimeter (ATIC)  

NASA Technical Reports Server (NTRS)

ATIC is a balloon-borne investigation of cosmic ray spectra, from below 50 GeV to near 100 TeV total energy, using a fully active Bismuth Gemmate (BGO) calorimeter. It is equipped with the first large area mosaic of small fully depleted silicon detector pixels capable of charge identification in cosmic rays from H to Fe. As a redundancy check for the charge identification and a coarse particle tracking system, three projective layers of x-y scintillator hodoscopes were employed, above, in the center and below a Carbon interaction 'target'. Very high energy gamma-rays and their energy spectrum may provide insight to the flux of extremely high energy neutrinos which will be investigated in detail with several proposed cubic kilometer scale neutrino observatories in the next decade.

Adams, J. H.; Ahn, E. J.; Bashindzhagyan, G.; Case, G.; Chang, J.; Christl, M.; Ellison, S.; Fazely, Ali R.; Ganel, O.; Gould, R.

2003-01-01

54

On Cosmic Ray Propagation  

NASA Astrophysics Data System (ADS)

Cosmic ray propagation is diffusive because of pitch angle scattering by waves. We demonstrate that if the high-amplitude magnetic turbulence with (delta B)/B ~ 1 is present on top of the mean field gradient, the diffusion becomes asymmetric. As an example, we solve this diffusion problem in one dimension analytically with a Markov chain analysis. The cosmic ray density markedly differs from the standard diffusion prediction. The equation for the continuous limit is also derived, which shows limitations of the convection-diffusion equation. There is an interesting connection of this problem to laboratory experimental studies of particle transport in multi-mirror machines. The implications of the results are discussed. Supported by grant DOE grant DE-FG02-07ER54940 and NSF grant AST-1209665.

Medvedev, Mikhail

2014-06-01

55

Origin of cosmic rays  

NASA Astrophysics Data System (ADS)

It is argued that there are three 'origins' of cosmic rays; the origin of the particles, the origin of the energy, and the site of the acceleration. The evidence for each origin is discussed and a plausible synthesis outlined for the particles of Galactic origin where the energy comes mainly (but not exclusively) from supernova explosions, the site of the acceleration is at strong collisionless shock waves, and the accelerated particles come from the interstellar and circumstellar material swept over by these shocks. If these shocks are capable (as indicated by recent observations and theoretical work) of significantly amplifying magnetic fields this picture appears capable of explaining the cosmic ray particles at all energies below the 'ankle' at 3 × 1018 eV. The particles above this energy are generally taken to be of extra-galactic origin and possible acceleration sites for these UHE particles are briefly discussed.

Drury, Luke O.'C.

2012-12-01

56

Cosmic Rays: "A Thin Rain of Charged Particles."  

ERIC Educational Resources Information Center

Discussed are balloons and electroscopes, understanding cosmic rays, cosmic ray paths, isotopes and cosmic-ray travel, sources of cosmic rays, and accelerating cosmic rays. Some of the history of the discovery and study of cosmic rays is presented. (CW)

Friedlander, Michael

1990-01-01

57

Detection of High Energy Cosmic Rays with Advanced Thin Ionization Calorimeter, ATIC  

NASA Technical Reports Server (NTRS)

The author presents preliminary results of the first flight of the Advanced Thin Ionization Calorimeter (ATIC). ATIC is a multiple, long duration balloon flight, investigation for the study of cosmic ray spectra from below 50 GeV to near 100 TeV total energy, using a fully active Bismuth Germanate (BGO) calorimeter. It is equipped with the first large area mosaic of small fully depleted silicon detector pads capable of charge identification of cosmic rays from H to Fe. As a redundancy check for the charge identification and a coarse particle tracking system, three projective layers of x-y scintillator hodoscopes were employed, above, in the center and below a Carbon interaction 'target'.

Adams, J. H.; Ahn, E. J.; Ahn, H. S.; Bashindzhagyan, G.; Case, G.; Chang, J.; Christl, M.; Ellison, S.; Fazely, A. R.; Ganel, O.

2002-01-01

58

Cosmic Necklaces and Ultrahigh Energy Cosmic Rays  

SciTech Connect

Cosmic necklaces are hybrid topological defects consisting of monopoles and strings, with two strings attached to each monopole. We argue that the cosmological evolution of necklaces may significantly differ from that of cosmic strings. The typical velocity of necklaces can be much smaller than the speed of light, and the characteristic scale of the network much smaller than the horizon. We estimate the flux of high-energy protons produced by monopole annihilation in the decaying closed loops. For some reasonable values of the parameters it is comparable to the observed flux of ultrahigh-energy cosmic rays. {copyright} {ital 1997} {ital The American Physical Society}

Berezinsky, V. [INFN, Laboratori Nazionali del Gran Sasso, 67010 Assergi (Antarctica) (Italy)] [INFN, Laboratori Nazionali del Gran Sasso, 67010 Assergi (Antarctica) (Italy); Vilenkin, A. [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155 (United States)] [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155 (United States)

1997-12-01

59

The optics and detector-simulation of the air fluorescence telescope FAMOUS for the detection of cosmic rays  

NASA Astrophysics Data System (ADS)

A sophisticated method for the observation of ultra-high-energy cosmic rays (UHECRs) is the fluorescence detection technique of extensive air showers (EAS). FAMOUS will be a small fluorescence telescope, instrumented with silicon photomultipliers (SiPMs) as highly-sensitive light detectors. In comparison to photomultiplier tubes, SiPMs promise to have a higher photon-detection-efficiency. An increase in sensitivity allows to detect more distant and lower energy showers which will contribute to an enrichment of the current understanding of the development of EAS and the chemical composition of UHECRs.

Niggemann, Tim; Hebbeker, Thomas; Lauscher, Markus; Meurer, Christine; Middendorf, Lukas; Schumacher, Johannes; Stephan, Maurice

2012-09-01

60

Antiprotons in cosmic rays  

NASA Technical Reports Server (NTRS)

Recent experimental observations and results are discussed. It was found that the approximately 50 antiprotons collected in balloon experiments to date have generated considerable theoretical interest. Clearly, confirmatory experiments and measurements over an extended energy range are required before definite conclusions are drawn. Antiproton measurements have a bearing on astrophysical problems ranging from cosmic ray propagation to issues of cosmological import. The next generation of balloon experiments and the Particle Astrophysics Magnet Facility being discussed for operation on NASA's space station should provide data and insights of highest interest.

Balasubrahmanyan, V. K.; Ormes, J. F.; Streitmatter, R. E.

1987-01-01

61

The Origin of Cosmic Rays  

ScienceCinema

Cosmic Rays reach the Earth from space with energies of up to more than 1020 eV, carrying information on the most powerful particle accelerators that Nature has been able to assemble. Understanding where and how cosmic rays originate has required almost one century of investigations, and, although the last word is not written yet, recent observations and theory seem now to fit together to provide us with a global picture of the origin of cosmic rays of unprecedented clarity. Here we will describe what we learned from recent observations of astrophysical sources (such as supernova remnants and active galaxies) and we will illustrate what these observations tell us about the physics of particle acceleration and transport. We will also discuss the “end” of the Galactic cosmic ray spectrum, which bridges out attention towards the so called ultra high energy cosmic rays (UHECRs). At ~1020 eV the gyration scale of cosmic rays in cosmic magnetic fields becomes large enough to allow us to point back to their sources, thereby allowing us to perform “cosmic ray astronomy”, as confirmed by the recent results obtained with the Pierre Auger Observatory. We will discuss the implications of these observations for the understanding of UHECRs, as well as some questions which will likely remain unanswered and will be the target of the next generation of cosmic ray experiments.

62

The Origin of Cosmic Rays  

ScienceCinema

Cosmic Rays reach the Earth from space with energies of up to more than 1020 eV, carrying information on the most powerful particle accelerators that Nature has been able to assemble. Understanding where and how cosmic rays originate has required almost one century of investigations, and, although the last word is not written yet, recent observations and theory seem now to fit together to provide us with a global picture of the origin of cosmic rays of unprecedented clarity. Here we will describe what we learned from recent observations of astrophysical sources (such as supernova remnants and active galaxies) and we will illustrate what these observations tell us about the physics of particle acceleration and transport. We will also discuss the ?end? of the Galactic cosmic ray spectrum, which bridges out attention towards the so called ultra high energy cosmic rays (UHECRs). At ~1020 eV the gyration scale of cosmic rays in cosmic magnetic fields becomes large enough to allow us to point back to their sources, thereby allowing us to perform ?cosmic ray astronomy?, as confirmed by the recent results obtained with the Pierre Auger Observatory. We will discuss the implications of these observations for the understanding of UHECRs, as well as some questions which will likely remain unanswered and will be the target of the next generation of cosmic ray experiments.

Pasquale Blasi

2010-01-08

63

Cosmic Ray Energetics And Mass  

NASA Astrophysics Data System (ADS)

The balloon-borne Cosmic Ray Energetics And Mass (CREAM) experiment was flown for ~161 days in six flights over Antarctica. High energy cosmic-ray data were collected over a wide energy range from ~ 10^10 to > 10^14 eV at an average altitude of ~38.5 km with ~3.9 g/cm2 atmospheric overburden. Cosmic-ray elements from protons (Z = 1) to iron nuclei (Z = 26) are separated with excellent charge resolution. Building on success of the balloon flights, the payload is being reconfigured for exposure on the International Space Station (ISS). This ISS-CREAM instrument is configured with the CREAM calorimeter for energy measurements, and four finely segmented Silicon Charge Detector layers for precise charge measurements. In addition, the Top and Bottom Counting Detectors (TCD and BCD) and Boronated Scintillator Detector (BSD) have been newly developed. The TCD and BCD are scintillator based segmented detectors to separate electrons from nuclei using the shower profile differences, while BSD distinguishes electrons from nuclei by detecting thermal neutrons that are dominant in nuclei induced showers. An order of magnitude increase in data collecting power is possible by utilizing the ISS to reach the highest energies practical with direct measurements. The project status including results from on-going analysis of existing data and future plans will be discussed.

Seo, Eun-Suk

2014-08-01

64

Detection of solar cosmic rays with the Mexico City neutron monitor  

NASA Astrophysics Data System (ADS)

We performed a search for unreported solar cosmic ray signals on the full database of the Mexico City neutron monitor from 1989 to 2012 and present a detailed analysis of the time series corresponding to GLE 54, where we found a statistically significative increment matching the onset time of the event, thus providing evidence of acceleration of >10 GeV particles by eruptive phenomena in the solar atmosphere. We also present an estimate of the rigidity spectrum of those particles based on the registers of other American sector neutron monitors.

Vargas-Cardenas, B.; Valdes-Galicia, J. F.

2013-05-01

65

Jupiter as a Giant Cosmic Ray Detector  

NASA Astrophysics Data System (ADS)

We explore the feasibility of using the atmosphere of Jupiter to detect ultra-high-energy cosmic rays (UHECRs). The large surface area of Jupiter allows us to probe cosmic rays of higher energies than previously accessible. Cosmic ray extensive air showers in Jupiter's atmosphere could in principle be detected by the Large Area Telescope (LAT) on the Fermi observatory. In order to be observed, these air showers would need to be oriented toward the Earth, and would need to occur sufficiently high in the atmosphere that the gamma rays can penetrate. We demonstrate that, under these assumptions, Jupiter provides an effective cosmic ray "detector" area of 3.3 × 107 km2. We predict that Fermi-LAT should be able to detect events of energy >1021 eV with fluence 10-7 erg cm-2 at a rate of about one per month. The observed number of air showers may provide an indirect measure of the flux of cosmic rays >~ 1020 eV. Extensive air showers also produce a synchrotron signature that may be measurable by Atacama Large Millimeter/submillimeter Array (ALMA). Simultaneous observations of Jupiter with ALMA and Fermi-LAT could be used to provide broad constraints on the energies of the initiating cosmic rays.

Rimmer, P. B.; Stark, C. R.; Helling, Ch.

2014-06-01

66

Cosmic Ray Neutron Flux Measurements  

NASA Astrophysics Data System (ADS)

Cosmic rays are high-energetic particles originating from outer space that bombard the upper atmosphere of the Earth. Almost 90% of cosmic ray particles consist of protons, electrons and heavy ions. When these particles hit the Earth's atmosphere, cascade of secondary particles are formed. The most abundant particles reach to the surface of the Earth are muons, electrons and neutrons. In recent years many research groups are looking into potential applications of the effects of cosmic ray radiation at the surface of the Earth [1, 2]. At Georgia State University we are working on a long-term measurement of cosmic ray flux distribution. This study includes the simultaneous measurement of cosmic ray muons, neutrons and gamma particles at the Earth surface in downtown Atlanta. The initial effort is focusing on the correlation studies of the cosmic ray particle flux distribution and the atmospheric weather conditions. In this presentation, I will talk about the development of a cosmic ray detector using liquid scintillator and the preliminary results. [4pt] [1] K.Borozdin, G.Hogan, C.Morris, W.Priedhorsky, A.Saunders, L.Shultz, M.Teasdale, ``Radiographic imaging with cosmic-ray muons'', Nature, Vol.422, p.277, Mar.2003[0pt] [2] Svensmark Henrik, Physical Review 81, 3, (1998)

Dayananda, Mathes

2009-11-01

67

Heavy Electrons in Cosmic Rays  

Microsoft Academic Search

Neddermeyer and Anderson1, on the basis of their experiments on the loss of energy by cosmic ray particles, have suggested that there are present in cosmic rays `new' particles of mass greater than that of an electron and less than that of a proton. In this note we give additional evidence for such a particle (some of which has previously

E. J. Williams; E. Pickup

1938-01-01

68

Cosmic ray propagation and containment  

NASA Technical Reports Server (NTRS)

The cosmic rays, an active gaseous component of the disk of the galaxy, are considered along with their propagation and containment as a part of the general dynamics of the disk. The sources of cosmic rays are a matter of speculation. The disk is inflated by the cosmic ray gas pressure comparable to the magnetic pressure, but the rate of inflation is unknown. The time spent by the individual cosmic ray particles in the disk is inversely proportional to the cosmic ray production rate. It is evident from the decay of Be(1c) that the cosmic rays circulate through a volume of space perhaps ten times the thickness of the gaseous disk, suggesting a magnetic halo extending out approximately 1 kpc from either face of the disk. The cosmic rays may be responsible for the halo by inflating the magnetic fields of the disk. Extension of the fields to 1 kpc would imply a high production rate and short life of cosmic rays in the dense gaseous disk of the galaxy.

Parker, E. N.

1976-01-01

69

Cosmic-Rays and Gamma Ray Bursts  

NASA Astrophysics Data System (ADS)

Cosmic-rays are subatomic particles of energies ranging between a few eV to hundreds of TeV. These particles register a power-law spectrum, and it seems that most of them originate from astrophysical galactic and extragalactic sources. The shock acceleration in superalfvenic astrophysical plasmas, is believed to be the main mechanism responsible for the production of the non-thermal cosmic-rays. Especially, the importance of the very high energy cosmic-ray acceleration, with its consequent gamma-ray radiation and neutrino production in the shocks of the relativistic jets of Gamma Ray Bursts, is a favourable theme of study. I will discuss the cosmic-ray shock acceleration mechanism particularly focusing on simulation studies of cosmic-ray acceleration occurring in the relativistic shocks of GRB jets.

Meli, A.

2013-07-01

70

Gamma rays, cosmic rays, and galactic structure  

NASA Technical Reports Server (NTRS)

Observations of cosmic and gamma radiation by SAS-2 satellite are summarized and analyzed to determine processes responsible for producing observed galactic radiation. In addition to the production of gamma rays in discrete galactic objects such as pulsars, there are three main mechanisms by which high-energy (greater than 100 MeV) radiation is produced by high-energy interactions involving cosmic rays in interstellar space. These processes, which produce what may be called diffuse galactic gamma-rays, are: (1) the decay of pi mesons produced by interactions of cosmic ray nucleons with interstellar gas nuclei; (2) the bremsstrahlung radiation produced by cosmic ray electrons interacting in the Coulomb fields of nuclei of interstellar gas atoms; and (3) Compton interactions between cosmic ray electrons and low-energy photons in interstellar space.

Stecker, F. W.

1977-01-01

71

The Highest Energy Cosmic Rays and Gamma Rays  

Microsoft Academic Search

Taking advantage of the dark skies near Dugway, Utah, the University of Utah's Fly's Eye Detector has been observing cosmic rays with energies above 3x 10(16) eV by detecting light from the nitrogen fluorescence from the Extensive Air Showers produced by cosmic rays. The detection of an event measured to have 3x 10(20) eV raises the question of whether the

S. F. Taylor; T. Abu-Zayyad; K. Belov; Z. Cao; G. Chen; M. A. Huang; C. C. H. Jui; D. B. Kieda; E. C. Loh; J. N. Matthews; M. Salamon; A. Salman; J. D. Smith; P. Sokolsky; P. Sommers; S. B. Thomas; L. R. Wiencke; D. J. Bird; R. W. Clay; B. R. Dawson; K. M. Simpson; C. R. Wilkinson; J. Boyer; E. J. Mannel; Y. Ho; W. Lee; T. O'Halloran; N. Hayashida; H. Hirasawa; F. Ishikawa; H. Lafoux; M. Nagano; D. Nishikawa; T. Ouchi; H. Ohoka; M. Ohnishi; N. Sakaki; M. Sasaki; H. Shimodaira; M. Teshima; R. Torii; T. Yamamoto; S. Yoshida; T. Yuda

1998-01-01

72

COSMIC-RAY TRANSPORT AND ANISOTROPIES  

SciTech Connect

We show that the large-scale cosmic-ray anisotropy at {approx}10 TeV can be explained by a modified Compton-Getting effect in the magnetized flow field of old supernova remnants. Cosmic rays arrive isotropically to the flow field and are then carried along with the flow to produce a large-scale anisotropy in the arrival direction. This approach suggests an optimum energy scale for detecting the anisotropy. Two key assumptions are that propagation is based on turbulence following a Kolmogorov law and that cosmic-ray interactions are dominated by transport via cosmic-ray-excited magnetic irregularities through the stellar wind of an exploding star and its shock shell. A prediction is that the amplitude is smaller at lower energies due to incomplete sampling of the velocity field and also smaller at larger energies due to smearing.

Biermann, Peter L. [MPI for Radioastronomy, Auf dem Huegel 69, D-53121 Bonn (Germany); Becker Tjus, Julia; Mandelartz, Matthias [Ruhr-Universitaet Bochum, Fakultaet fuer Physik and Astronomie, Theoretische Physik I, D-44780 Bochum (Germany); Seo, Eun-Suk [Department of Physics, University of Maryland, College Park, MD 20742 (United States)

2013-05-10

73

The ALTA cosmic ray experiment electronics system  

NASA Astrophysics Data System (ADS)

Understanding the origin and propagation of high-energy cosmic rays is a fundamental area of astroparticle physics with major unanswered questions. The study of cosmic rays with energy more than 1014 eV, probed only by ground-based experiments, has been restricted by the low particle flux. The Alberta Large-area Time-coincidence Array (ALTA) uses a sparse array of cosmic ray detection stations located in high schools across a large geographical area to search for non-random high-energy cosmic ray phenomena. Custom-built ALTA electronics is based on a modular board design. Its function is to control the detectors at each ALTA site allowing precise measurements of event timing and energy in the local detectors as well as time synchronization of all of the sites in the array using the global positioning system.

Brouwer, W.; Burris, W. J.; Caron, B.; Hewlett, J.; Holm, L.; Hamilton, A.; McDonald, W. J.; Pinfold, J. L.; Price, P.; Schaapman, J. R.; Sibley, L.; Soluk, R. A.; Wampler, L. J.

2005-03-01

74

Cosmic rays: 1912-2012  

NASA Astrophysics Data System (ADS)

One hundred years ago, using balloon flights up to 5 kilometers altitude, Victor Hess demonstrated that the intensity of penetrating ionizing radiation increased with altitude, indicating that Earth is exposed to high-energy radiation from space [Hess, 1912]. Since that observation, these “cosmic rays” have enabled discoveries basic to elementary particle physics and astrophysics. This discovery earned Hess the 1936 Nobel Prize in Physics, shared with Carl Anderson, who discovered the positron among the secondary cosmic rays near the ground [Anderson, 1933]. Then, the only known ionizing radiation with range in air more than about 30 centimeters was the ? ray (electromagnetic radiation with energy above about 100 kiloelectron volts), so the radiation from space was assumed to be ? rays and was called “cosmic rays.” That name has stuck, although the “cosmic rays” studied today are not actually rays but particles. Indeed, ? rays do impinge on Earth, and ? ray astronomy is a burgeoning area of astrophysics, but the term “cosmic rays” continues to apply to the charged particles that make up the bulk of the incident ionizing radiation.

Israel, Martin H.

2012-09-01

75

Studies of Cosmic Rays with GeV Gamma Rays.  

National Technical Information Service (NTIS)

We describe the role of GeV gamma-ray observations with GLAST-LAT (Gamma-ray Large Area Space Telescope - Large Area Telescope) in identifying interaction sites of cosmic-ray proton (or hadrons) with interstellar medium (ISM). We expect to detect gamma ra...

H. Tajima J. Chiang J. Cohen-Tanugi S. Finazzi T. Kamae

2007-01-01

76

Astrophysics of Galactic Charged Cosmic Rays  

NASA Astrophysics Data System (ADS)

A review is given of the main properties of the charged component of galactic cosmic rays, particles detected at Earth with an energy spanning from tens of MeV up to about 1019 eV. After a short introduction to the topic and a historical overview, the properties of cosmic rays are discussed with respect to different energy ranges. The origin and the propagation of nuclei in the Galaxy are dealt with from a theoretical point of view. The mechanisms leading to the acceleration of nuclei by supernova remnants and to their subsequent diffusion through the inhomogeneities of the galactic magnetic field are discussed, and some clue is given on the predictions and observations of fluxes of antimatter, both from astrophysical sources and from dark matter annihilation in the galactic halo.The experimental techniques and instrumentations employed for the detection of cosmic rays at Earth are described. Direct methods are viable up to ? 1014 eV, by means of experiments flown on balloons or satellites, while above that energy, due to their very low flux, cosmic rays can be studied only indirectly by exploiting the particle cascades they produce in the atmosphere.The possible physical interpretation of the peculiar features observed in the energy spectrum of galactic cosmic rays, and in particular the so-called "knee" at about 4 ×1015 eV, is discussed. A section is devoted to the region between about 1018 and 1019 eV, which is believed to host the transition between galactic and extragalactic cosmic rays. The conclusion gives some perspectives on the cosmic ray astrophysics field. Thanks to a wealth of different experiments, this research area is living a very flourishing era. The activity is exciting both from the theoretical and the instrumental sides, and its interconnection with astronomy, astrophysics, and particle physics experiences nonstop growth.

Castellina, Antonella; Donato, Fiorenza

77

Cosmic Ray Identification and Ramp-fitting in JWST Data  

NASA Astrophysics Data System (ADS)

Cosmic rays are expected to significantly affect on-orbit JWST detectors as the cosmic-ray environment does not benefit from shielding by the Earth's magnetic field. Data is read non-destructively (up-the-ramp) so cosmic rays can be recognized as jumps in the pixel ramps as signal accumulates. Because the effect of a cosmic ray is to add a large and unpredictable number of counts to the signal, it is important to correctly flag cosmic rays to enable valid count rates to be calculated for science pixel data. Once the cosmic rays are identified, a fit can be performed for the data between cosmic ray-affected reads, allowing the count rate for each pixel to be estimated. In lieu of having on-orbit data on which to test cosmic ray rejection algorithms and fitting algorithms, a set of Python scripts was written to generate artificial datasets that include realistic celestial sources and cosmic rays. An investigation was made into ways of detecting cosmic rays, and then how to measure the underlying count rate signal in the presence of these jumps. As the on-orbit datasets will be large, techniques to reduce the processing time by reducing the memory requirements and reordering the data have been investigated. Cosmic ray rejection and ramp fitting will be incorporated into the JWST Calibration pipeline to reduce on-orbit data.

Grumm, D.; Greenfield, P.

2012-09-01

78

Calculation of cosmic ray induced single event upsets: Program CRUP (Cosmic Ray Upset Program)  

NASA Astrophysics Data System (ADS)

This report documents PROGRAM CRUP, COSMIC RAY UPSET PROGRAM. The computer program calculates cosmic ray induced single-event error rates in microelectronic circuits exposed to several representative cosmic-ray environments.

Shapiro, P.

1983-09-01

79

Cosmic X-ray physics  

Microsoft Academic Search

A progress report of research activities carried out in the area of cosmic X-ray physics is presented. The Diffuse X-ray Spectrometer DXS which has been flown twice as a rocket payload is described. The observation times proved to be too small for meaningful X-ray data to be obtained. Data collection and reduction activities from the Ultra-Soft X-ray background (UXT) instrument

D. McCammon; D. P. Cox; W. L. Kraushaar; W. T. Sanders

1985-01-01

80

Cosmic X-Ray Physics.  

National Technical Information Service (NTIS)

A progress report of research activities carried out in the area of cosmic X-ray physics is presented. The Diffuse X-ray Spectrometer DXS which has been flown twice as a rocket payload is described. The observation times proved to be too small for meaning...

D. Mccammon D. P. Cox W. L. Kraushaar W. T. Sanders

1985-01-01

81

THE STUDY OF COSMIC ? RAYS  

Microsoft Academic Search

CONTENTS 1. Introduction 630 2. Main Cosmic ?-ray (CGR) Production Processes. Interaction of CGR with Interstellar and Intergalactic Matter 631 3. Methods of Study of CGR 632 4. Comparability of Experimental Results. Calibration of ? Detectors 634 5. Conditions of CGR Study. Atmospheric and Local Backgrounds 635 6. Results of Diffuse CGR Measurement in Balloons. The ?-ray Flux Extrapolated to

A M Galper; V G Kirillov-Ugryumov; B I Luchkov; O F Prilutski?

1972-01-01

82

Origin and propagation of extremely high-energy cosmic rays  

Microsoft Academic Search

Cosmic-ray particles with energies in excess of 1020eV have been detected. The sources as well as the physical mechanism(s) responsible for endowing cosmic-ray particles with such enormous energies are unknown. This report gives a review of the physics and astrophysics associated with the questions of origin and propagation of these extremely high-energy (EHE) cosmic-rays in the Universe. After a brief

Pijushpani Bhattacharjee; Guenter Sigl

2000-01-01

83

Cosmic Rays from Cygnus X-3  

Microsoft Academic Search

Today many investigators adhere to the idea that cosmic rays receive all their energy from discrete sources with interstellar space acting only as a diffusive medium. An object that accelerates particles to cosmic-ray velocities will almost inevitably produce gamma rays as well. Hence, gamma rays are therefore an effective probe of the source of cosmic radiation even though they account

P. Kevin MacKeown; Trevor C. Weekes

1985-01-01

84

Detecting a mass change inside a volcano by cosmic-ray muon radiography (muography): First results from measurements at Asama volcano, Japan  

Microsoft Academic Search

A visual detection and monitoring of volcanic eruptions is the most essential information. In February 2, 2009, Asama volcano, Japan erupted and a large amount of volcanic ash was ejected from the vent. We have observed the activity at Asama since October 12, 2008. For eruption monitoring we used cosmic-ray muon radiography (muography), a new volcano monitoring system recently developed

Hiroyuki K. M. Tanaka; Tomihisa Uchida; Manobu Tanaka; Minoru Takeo; Jun Oikawa; Takao Ohminato; Yosuke Aoki; Etsuro Koyama; Hiroshi Tsuji

2009-01-01

85

The microphysics and macrophysics of cosmic rays  

SciTech Connect

This review paper commemorates a century of cosmic ray research, with emphasis on the plasma physics aspects. Cosmic rays comprise only ?10{sup ?9} of interstellar particles by number, but collectively their energy density is about equal to that of the thermal particles. They are confined by the Galactic magnetic field and well scattered by small scale magnetic fluctuations, which couple them to the local rest frame of the thermal fluid. Scattering isotropizes the cosmic rays and allows them to exchange momentum and energy with the background medium. I will review a theory for how the fluctuations which scatter the cosmic rays can be generated by the cosmic rays themselves through a microinstability excited by their streaming. A quasilinear treatment of the cosmic ray–wave interaction then leads to a fluid model of cosmic rays with both advection and diffusion by the background medium and momentum and energy deposition by the cosmic rays. This fluid model admits cosmic ray modified shocks, large scale cosmic ray driven instabilities, cosmic ray heating of the thermal gas, and cosmic ray driven galactic winds. If the fluctuations were extrinsic turbulence driven by some other mechanism, the cosmic ray background coupling would be entirely different. Which picture holds depends largely on the nature of turbulence in the background medium.

Zweibel, Ellen G. [Departments of Astronomy and Physics and Center for Magnetic Self-Organization, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)] [Departments of Astronomy and Physics and Center for Magnetic Self-Organization, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

2013-05-15

86

Cosmic rays at fluid discontinuities  

NASA Technical Reports Server (NTRS)

Cosmic-ray transport near discontinuities in the background fluid velocity is considered. Matching conditions for the cosmic-ray distribution are derived for both shear and compressive (shock) discontinuities, keeping terms to second order in the ratio of fluid speed to energetic-particle speed. Acceleration is found at shear discontinuities, which is not present in the first-order theory, and a modification of the matching condition at shocks. If there is no particle source concentrated at a shock, the new condition reduces to that obtained from first-order theory. Monte Carlo simulations show good agreement with the theory.

Jokipii, J. R.; Kota, J.; Morfill, G.

1989-01-01

87

Tensor anisotropy of cosmic rays  

NASA Astrophysics Data System (ADS)

Long-termobservations of the muon intensity of galactic cosmic rays at the Nagoya (35°10' N, 136°58' E) and Yakutsk (62°01' N, 129°43' E) stations have revealed amplitude-phase annual and semiannual oscillations of the semidiurnal variation. These oscillations are attributable to the properties of the cosmic-ray anisotropy tensor that result from shielding by the interplanetary magnetic field and solar-wind shear flow. The mentioned tensor is also shown to have a north-south asymmetry.

Krymsky, G. F.; Krivoshapkin, P. A.; Gerasimova, S. K.; Gololobov, P. Yu.

2014-04-01

88

Cosmic very high-energy gamma rays  

Microsoft Academic Search

The article gives a brief overview, aimed at nonspecialists, about the goals and selected recent results of the detection of very-high energy gamma-rays (energies above 100 GeV) with ground based detectors. The stress is on the physics questions, especially the origin of Galactic Cosmic Rays and the emission of TeV gamma-radiation from active galaxies. Moreover some particle-physics questions which are

R. Plaga

1998-01-01

89

People Interview: Cosmic rays uncover universe theories  

NASA Astrophysics Data System (ADS)

INTERVIEW Cosmic rays uncover universe theories David Smith talks to Paula Chadwick about why she is fascinated by cosmic and gamma rays, and how this is the year that their profile is going to be raised

2012-07-01

90

Evaluation of Galactic Cosmic Ray Models  

NASA Technical Reports Server (NTRS)

Models of the galactic cosmic ray spectra have been tested by comparing their predictions to an evaluated database containing more than 380 measured cosmic ray spectra extending from 1960 to the present.

Adams, James H., Jr.; Heiblim, Samuel; Malott, Christopher

2009-01-01

91

The Heliosphere and Galactic Cosmic Rays  

NASA Video Gallery

The heliosphere deflects galactic cosmic rays from entering the system. Galactic cosmic rays are a very high energy form of particle radiation that are extremely difficult to shield against and are...

92

Cosmic Ray Study with the PAMELA Experiment  

NASA Astrophysics Data System (ADS)

In six years of data collection years in space, the experiment PAMELA has discovered very interesting features in cosmic rays, namely in the fluxes of protons, helium, electrons, that might change our basic vision of the mechanisms of production, acceleration and propagation of cosmic rays in the Galaxy. In addition, PAMELA measurements of cosmic antiproton and positron fluxes are setting strong constraints to the nature of Dark Matter. The continuous particle detection is allowing a constant monitoring of the solar activity and detailed study of the solar modulation for a long period, giving important improvements to the comprehension of the heliosphere mechanisms. PAMELA is also measuring the radiation environment around the Earth, and has recently discovered an antiproton radiation belt.

Picozza, P.; Marcelli, L.; Adriani, O.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Boezio, M.; Bogomolov, E. A.; Bongi, M.; Bonvicini, V.; Borisov, S.; Bottai, S.; Bruno, A.; Cafagna, F.; Campana, D.; Carbone, R.; Carlson, P.; Casolino, M.; Castellini, G.; De Pascale, M. P.; De Santis, C.; De Simone, N.; Di Felice, V.; Galper, A. M.; Grishantseva, L.; Jerse, G.; Karelin, A. V.; Kheymits, M. D.; Koldashov, S. V.; Y Krutkov, S.; Kvashnin, A. N.; Leonov, A.; Malakhov, V.; Mayorov, A. G.; Menn, W.; Mikhailov, V. V.; Mocchiutti, E.; Monaco, A.; Mori, N.; Nikonov, N.; Osteria, G.; Palma, F.; Papini, P.; Pearce, M.; Pizzolotto, C.; Ricci, M.; Ricciarini, S. B.; Sarkar, R.; Rossetto, L.; Simon, M.; Sparvoli, R.; Spillantini, P.; Stozhkov, Y. I.; Vacchi, A.; Vannuccini, E.; Vasilyev, G.; Voronov, S. A.; Yurkin, Y. T.; Wu, J.; Zampa, G.; Zampa, N.; Zverev, V. G.

2013-02-01

93

The Cosmic Ray Electron Excess  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the possible sources for the apparent excess of Cosmic Ray Electrons. The presentation reviews the Advanced Thin Ionization Calorimeter (ATIC) instrument, the various parts, how cosmic ray electrons are measured, and shows graphs that review the results of the ATIC instrument measurement. A review of Cosmic Ray Electrons models is explored, along with the source candidates. Scenarios for the excess are reviewed: Supernova remnants (SNR) Pulsar Wind nebulae, or Microquasars. Each of these has some problem that mitigates the argument. The last possibility discussed is Dark Matter. The Anti-Matter Exploration and Light-nuclei Astrophysics (PAMELA) mission is to search for evidence of annihilations of dark matter particles, to search for anti-nuclei, to test cosmic-ray propagation models, and to measure electron and positron spectra. There are slides explaining the results of Pamela and how to compare these with those of the ATIC experiment. Dark matter annihilation is then reviewed, which represent two types of dark matter: Neutralinos, and kaluza-Kline (KK) particles, which are next explained. The future astrophysical measurements, those from GLAST LAT, the Alpha Magnetic Spectrometer (AMS), and HEPCAT are reviewed, in light of assisting in finding an explanation for the observed excess. Also the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) could help by revealing if there are extra dimensions.

Chang, J.; Adams, J. H.; Ahn, H. S.; Bashindzhagyan, G. L.; Christl, M.; Ganel, O.; Guzik, T. G.; Isbert, J.; Kim, K. C.; Kuznetsov, E. N.; Panasyuk, M. I.; Panov, A. D.; Schmidt, W. K. H.; Seo, E. S.; Sokolskaya, N. V.; Watts, J. W.; Wefel, J. P.; Wu, J.; Zatsepin, V. I.

2008-01-01

94

Cosmic rays and hadronic interactions  

SciTech Connect

The cosmic ray spectrum extends to particles with energy E{approx} 10{sup 20} eV, that corresponds (assuming that the primary particle is a proton) to a nucleon-nucleon c.m. energy {radical}(s) Asymptotically-Equal-To 430TeV, 50 times higher than the current LHC energy. These very high energy particles can be studied via the observation of the showers they generate in the atmosphere. The interpretation of the data requires therefore the modeling of hadronic interactions in an energy range beyond what can be studied in accelerator experiments. The theoretical problem of estimating the relevant properties of hadronic interactions in this energy range is therefore of central importance for the interpretation of the cosmic ray data. Viceversa, it is in principle possible to obtain information about hadronic interactions from the cosmic ray observations, but this program has to confront the fact that the (freely available) cosmic ray beam has an unknown energy spectrum and an unknown mass composition.

Lipari, Paolo [INFN sez. Roma, and Dipartimento di Fisica, Universita di Roma Sapienza (Italy)

2013-03-25

95

The Stability of Cosmic Ray Precursors  

NASA Astrophysics Data System (ADS)

I consider the stability of cosmic ray precursors near shocks propagating in a high-? plasma. It is shown that the interplay between cosmic ray effects and the classical firehose and mirror instabilities lead to a more vigorous instability. Consequences for cosmic ray acceleration are discussed.

Achterberg, A.

2013-01-01

96

Cosmic Rays and Space Situational Awareness in Europe  

Microsoft Academic Search

In this paper European space weather activities are sketched and the contribution of cosmic ray research and technology to the European space situational awareness programme is described. Especially the cosmic ray muon detection technique is studied - on ground and in future space based -, because it is considered to be very useful for coronal mass ejection forecast in the

F. Jansen; J. Behrens

97

Magnetic fields and cosmic rays in cooling flows  

Microsoft Academic Search

Cooling flows are regions where the importance of non-thermal intra-cluster medium components such as magnetic fields and cosmic rays may be strongest within a galaxy cluster. They are also regions where such components are best detectable due to the high gas density which influences Faraday rotation measurements of magnetic fields and secondary particle production in hadronic interactions of cosmic ray

Torsten Ensslin; Corina Vogt; Christoph Pfrommer

2003-01-01

98

Magnetic Fields and Cosmic Rays in Galaxy Cluster Cooling Flows  

Microsoft Academic Search

Cooling flows are regions where the importance of non-thermal intracluster medium components such as magnetic fields and cosmic rays may be strongest within a galaxy cluster. They are also regions where such components are best detectable due to the high gas density which influences Faraday rotation measurements of magnetic fields and secondary particle production in hadronic interactions of cosmic ray

T. A. Enßlin; C. Vogt; C. Pfrommer

2004-01-01

99

Research in cosmic and gamma ray astrophysics  

NASA Technical Reports Server (NTRS)

Discussed here is research in cosmic ray and gamma ray astrophysics at the Space Radiation Laboratory (SRL) of the California Institute of Technology. The primary activities discussed involve the development of new instrumentation and techniques for future space flight. In many cases these instrumentation developments were tested in balloon flight instruments designed to conduct new investigations in cosmic ray and gamma ray astrophysics. The results of these investigations are briefly summarized. Specific topics include a quantitative investigation of the solar modulation of cosmic ray protons and helium nuclei, a study of cosmic ray positron and electron spectra in interplanetary and interstellar space, the solar modulation of cosmic rays, an investigation of techniques for the measurement and interpretation of cosmic ray isotopic abundances, and a balloon measurement of the isotopic composition of galactic cosmic ray boron, carbon, and nitrogen.

Stone, Edward C.; Mewaldt, Richard A.; Prince, Thomas A.

1992-01-01

100

Launch in Orbit of NINA detector for cosmic ray study  

Microsoft Academic Search

The apparatus NINA, on board the Russian satellite Resurs-O1 n.4, is in orbit since July 10th, 1998. Its scientific scope is to study the low energy component of cosmic ray nuclei. The polar orbit of the satellite allows the telescope to detect particles of different nature during its revolution: galactic cosmic rays, solar energetic particles, trapped and untrapped anomalous cosmic

Casolino Marco

1999-01-01

101

A focussing iron line crystal spectrometer for Spacelab. [cosmic X-ray detection  

NASA Technical Reports Server (NTRS)

A crystal spectrometer system is described which employs conical focusing of 12 curved LiF crystal panels to minimize the detector size and reduce the background counting rate. The wavelength range from 1.70 to 1.98 A is covered, including the resonance lines of Fe XXV and Fe XXVI as well as the Fe I K-alpha line and absorption edge. Operation of the spectrometer is discussed, noting that diffracted X-rays are registered in one-dimensional position-sensitive detectors and that the arrival position of a photon in a detector is related to its wavelength due to the fixed curvature of the crystal panels in the dispersion plane. Some characteristics of the multianode position-sensitive detectors are reviewed along with the crystal arrangement and mounting. The instrument sensitivity is evaluated in relation to the strengths of 6.7-keV emission features detected by the Ariel 5 and OSO 8 proportional-counter spectrometers.

Catura, R. C.; Culhane, J. L.; Rapley, C. G.; Gabriel, A. H.; Walker, A. B. C., Jr.; Woodgate, B. E.

1977-01-01

102

Cosmic x ray physics  

NASA Technical Reports Server (NTRS)

This final report covers the period 1 January 1985 - 31 March 1992. It is divided into the following sections: the soft x-ray background; proportional counter and filter calibrations; sounding rocket flight preparations; new sounding rocket payload: x-ray calorimeter; and theoretical studies. Staff, publications, conference proceedings, invited talks, contributed talks, colloquia and seminars, public service lectures, and Ph. D. theses are listed.

Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1992-01-01

103

The detection of high charge cosmic ray nuclei. [by balloon-borne electronic particle telescope  

NASA Technical Reports Server (NTRS)

A large-area, light-weight electronic particle telescope was flown on a high altitude balloon in the summer of 1974 to study the heavy nuclei in the cosmic radiation. This telescope consisted of a double Cerenkov-double scintillator array composed of four 1.22 m diameter disk radiators mounted in light diffusion boxes, each looked at by multiple photomultipliers. The impact point of each particle on the scintillation radiators was determined by studying the relative signals observed by three equally spaced peripheral photomultipliers and one mounted at the center of the diffusion boxes. This telescope was flown in a configuration having a geometric factor of 0.45 sq m sr and observed some 5 x 10 to the 4 nuclei with Z exceeding 14 in a 11 hr exposure. The response and sensitivity of this telescope are discussed in detail.

Scarlett, W. R.; Freier, P. S.; Waddington, C. J.

1975-01-01

104

Cosmic ray variations during PCA type absorption  

NASA Technical Reports Server (NTRS)

It is shown based on data on the cosmic-ray neutron component, ionospheric soundings, and measurements of cosmic radio-emission absorption at Vostok station (Antarctica) that the ionization of the lower ionosphere increases during low intensity of Forbush-type cosmic rays. This is manifested in increased absorption and the appearance of strong sporadic layers in the E-region.

Kozin, I. D.

1972-01-01

105

Charged Cosmic Rays and Neutrinos  

NASA Astrophysics Data System (ADS)

High-energy neutrino astronomy has grown up, with IceCube as one of its main experiments having sufficient sensitivity to test "vanilla" models of astrophysical neutrinos. I review predictions of neutrino fluxes as well as the status of cosmic ray physics. I comment also briefly on an improvement of the Fermi-LAT limit for cosmogenic neutrinos and on the two neutrino events presented by IceCube first at "Neutrino 2012".

Kachelrieß, M.

2013-04-01

106

Visual Sensations Produced by Cosmic Ray Muons  

Microsoft Academic Search

IN 1961, D'Arcy and Porter1 demonstrated that when single cosmic ray muons passed through the eyes of supine, dark-adapted observers, a small proportion produced a detectable visual sensation. The effect was ascribed either to the production of Cherenkov light in the eye media by the relativistic, singly charged particles or to some form of direct stimulation of the retina. Interest

W. N. Charman; Christina M. Rowlands

1971-01-01

107

Ultrahigh energy cosmic rays from topological defects--cosmic strings, monopoles, necklaces, and all that  

SciTech Connect

The topological defect scenario of origin of the observed highest energy cosmic rays is reviewed. Under a variety of circumstances, topological defects formed in the early Universe can be sources of very massive particles in the Universe today. The decay products of these massive particles may be responsible for the observed highest energy cosmic ray particles above 10{sup 20} eV. Some massive particle production processes involving cosmic strings and magnetic monopoles are discussed. We also discuss the implications of results of certain recent numerical simulations of evolution of cosmic strings. These results (which remain to be confirmed by independent simulations) seem to show that massive particle production may be a generic feature of cosmic strings, which would make cosmic strings an inevitable source of extremely high energy cosmic rays with potentially detectable flux. At the same time, cosmic strings are severely constrained by the observed cosmic ray flux above 10{sup 20} eV, if massive particle radiation is the dominant energy loss mechanism for cosmic strings.

Bhattacharjee, Pijushpani [Laboratory for High Energy Astrophysics, NASA/Goddard Space Flight Center, Code 661, Greenbelt, Maryland 20771 (United States); Indian Institute of Astrophysics, Bangalore-560 034 (India)

1998-06-15

108

First results from the microwave air yield beam experiment (MAYBE): Measurement of GHz radiation for ultra-high energy cosmic ray detection  

NASA Astrophysics Data System (ADS)

We present measurements of microwave emission from an electron-beam induced air plasma performed at the 3 MeV electron Van de Graaff facility of the Argonne National Laboratory. Results include the emission spectrum between 1 and 15 GHz, the polarization of the microwave radiation and the scaling of the emitted power with respect to beam intensity. MAYBE measurements provide further insight on microwave emission from extensive air showers as a novel detection technique for Ultra-High Energy Cosmic Rays.

Williams, C.; Bohá?ová, M.; Bonifazi, C.; Cataldi, G.; Chemerisov, S.; de Mello Neto, J. R. T.; Facal San Luis, P.; Fox, B.; Gorham, P. W.; Hojvat, C.; Hollon, N.; Meyhandan, R.; Monasor, M.; Rouillé d'Orfeuil, B.; Santos, E. M.; Pochez, J.; Privitera, P.; Spinka, H.; Verzi, V.; Zhou, J.

2013-06-01

109

Future projects for the highest energy cosmic rays  

NASA Astrophysics Data System (ADS)

The discovery of the highest energy cosmic rays above 1020eV by Fly's Eye and AGASA experiments gave us a strong motivation to propose next generation detectors. The detection techniques for the highest energy cosmic rays, and the future projects (Auger, TA/snake, OWL/Air Watch) will be reviewed. In order to clarify the source of these energetic cosmic rays, the capabilities of neutrino detection and the primary particle identification become essential. The characteristics of showers induced by neutrinos and gammas are also discussed.

Teshima, Masahiro

1998-12-01

110

Cosmic Connections: from Cosmic Rays to Gamma Rays, Cosmic Backgrounds and Magnetic Fields  

NASA Astrophysics Data System (ADS)

Combined data from gamma-ray telescopes and cosmic-ray detectors have produced some new surprising insights regarding intergalactic and galactic magnetic fields, as well as extragalactic background light. We review some recent advances, including a theory explaining the hard spectra of distant blazars and the measurements of intergalactic magnetic fields based on the spectra of distant sources. Furthermore, we discuss the possible contribution of transient galactic sources, such as past gamma-ray bursts and hypernova explosions in the Milky Way, to the observed flux of ultrahigh-energy cosmic-rays nuclei. The need for a holistic treatment of gamma rays, cosmic rays, and magnetic fields serves as a unifying theme for these seemingly unrelated phenomena.

Kusenko, Alexander

2013-01-01

111

Searching for Galactic Cosmic-Ray Pevatrons with Multi-TeV Gamma Rays and Neutrinos  

Microsoft Academic Search

The recent H.E.S.S. detections of supernova remnant shells in TeV gamma-rays confirm the theoretical predictions that supernova remnants can operate as powerful cosmic-ray accelerators. If these objects are responsible for the bulk of galactic cosmic rays, then they should accelerate protons and nuclei to 1015 eV and beyond, i.e., act as cosmic PeVatrons. The model of diffusive shock acceleration allows,

Stefano Gabici; Felix A. Aharonian

2007-01-01

112

Cosmic-ray-modified supernova remnant shocks  

NASA Technical Reports Server (NTRS)

The evolution of cosmic-ray-modified SNRs during the early Sedov phase is investigated using the time-dependent, two-fluid model for diffusive shock acceleration. Consideration is given to the sensitivity of net acceleration efficiency to model assumptions regarding density structure of the external medium as well as time dependence in the diffusion coefficient and the cosmic-ray adiabatic index. Of the model assumptions explored, the greatest sensitivity was found to time variations in the specific heat ratio to cosmic rays. It was found that if tau is greater than or approximately equal to few times 100, dynamically significant cosmic-ray pressures are produced early in the Sedov inefficient cosmic-ray accelerators. For the SNR models under consideration, the total energy channeled into the cosmic rays can be of order 10 percent of the initial blast energy for both the uniform density and inverse-square density interstellar medium models.

Jones, T. W.; Kang, Hyesung

1992-01-01

113

Galactic cosmic ray composition and energy spectra  

NASA Technical Reports Server (NTRS)

Galactic cosmic ray nuclei represent a significant risk to long-duration spaceflight outside the magnetosphere. We review briefly existing measurements of the composition and energy spectra of heavy cosmic ray nuclei, pointing out which species and energy ranges are most critical to assessing cosmic ray risks for spaceflight. Key data sets are identified and a table of cosmic ray abundances is presented for elements from H to Ni (Z = 1 to 28). Because of the 22-year nature of the solar modulation cycle, data from the approaching 1998 solar minimum is especially important to reducing uncertainties in the cosmic ray radiation hazard. It is recommended that efforts to model this hazard take advantage of approaches that have been developed to model the astrophysical aspects of cosmic rays.

Mewaldt, R. A.

1994-01-01

114

Cloud chamber visualization of primary cosmic rays  

SciTech Connect

From 1948 until 1963, cloud chambers were carried to the top of the atmosphere by balloons. From these flights, which were begun by Edward P. Ney at the University of Minnesota, came the following results: discovery of heavy cosmic ray nuclei, development of scintillation and cherenkov detectors, discovery of cosmic ray electrons, and studies of solar proton events. The history of that era is illustrated here by cloud chamber photographs of primary cosmic rays.

Earl, James A. [Department of Astronomy, University of Maryland, College Park MD (United States)

2013-02-07

115

Earth's magnetic field as a radiator to detect cosmic ray electrons of energy greater than 10 to the 12th eV  

NASA Technical Reports Server (NTRS)

Synchrotron emission by a high-energy electron in the geomagnetic field and its dependence upon different arrival directions over Palestine, Texas, where major balloon-borne experiments are being conducted, is studied. The dependence of detector response on the arrival direction of electron, the different criteria which are adopted to identify an electron event, the area of the detector, and the energy of the electron are discussed. An omnidirectional circular detector is used to examine whether it is possible to determine the energy of an electron without knowing its arrival direction. The collecting power of a detector is estimated as a function of the energy of electrons for different detector areas with different selection criteria, and this information is used to calculate the event rates expected by folding in the energy spectrum of cosmic ray electrons to show the viability of detecting cosmic ray electrons at energies greater than a few TeV.

Balasubrahmanyan, V. K.; Stephens, S. A.

1983-01-01

116

GEANT4 Simulation of a Cosmic Ray Muon Tomography System With Micro-Pattern Gas Detectors for the Detection of High-Z Materials  

NASA Astrophysics Data System (ADS)

Muon Tomography (MT) based on the measurement of multiple scattering of atmospheric cosmic ray muons traversing shipping containers is a promising candidate for identifying threatening high-Z materials. Since position-sensitive detectors with high spatial resolution should be particularly suited for tracking muons in an MT application, we propose to use compact micro-pattern gas detectors, such as Gas Electron Multipliers (GEMs), for muon tomography. We present a detailed GEANT4 simulation of a GEM-based MT station for various scenarios of threat material detection. Cosmic ray muon tracks crossing the material are reconstructed with a Point-Of-Closest-Approach algorithm to form 3D tomographic images of the target material. We investigate acceptance, Z-discrimination capability, effects of placement of high-Z material and shielding materials inside the cargo, and detector resolution effects for such a MT station.

Hohlmann, Marcus; Ford, Patrick; Gnanvo, Kondo; Helsby, Jennifer; Pena, David; Hoch, Richard; Mitra, Debasis

2009-06-01

117

A novel technique to detect special nuclear material using cosmic rays  

NASA Astrophysics Data System (ADS)

Resistive plate chambers (RPCs) are widely used in high energy physics for both tracking and triggering purposes, due to their excellent time resolution, rate capability, and good spatial resolution. RPCs can be produced cost-effectively on large scales, are of rugged build, and have excellent detection efficiency for charged particles. Our group has successfully built a muon scattering tomography (MST) prototype, using 12 RPCs to obtain tracking information of muons going through a target volume of ∼ 50 cm × 50 cm × 70 cm, reconstructing both the incoming and outgoing muon tracks. The required spatial granularity is achieved by using 330 readout strips per RPC with 1.5 mm pitch. The RPCs have shown an efficiency above 99% and an estimated intrinsic resolution below 1.1 mm. Due to these qualities, RPCs serve as excellent candidates for usage in volcano radiography.

Thomay, C.; Baesso, P.; Cussans, D.; Davies, J.; Glaysher, P.; Quillin, S.; Robertson, S.; Steer, C.; Vassallo, C.; Velthuis, J.

2012-12-01

118

Propagation of cosmic rays in the galaxy  

NASA Technical Reports Server (NTRS)

The characteristics of a model for analyzing the propagation of cosmic rays are discussed. The requirements for analyzing the relevant observational data on cosmic rays are defines as: (1) the chemical and isotopic composition of cosmic rays as a function of energy, (2) the flux and energy spectrum of the individual nucleonic components, (3) the flux and energy spectrum of the electronic component, (4) the cosmic ray prehistory, and (5) the degree of isotropy in their arrival directions as a function of energy. It is stated that the model which has been able to bring to pass the greatest measure of success is the galactic confinement model.

Daniel, R. R.; Stephens, S. A.

1974-01-01

119

High-energy cosmic ray interactions  

SciTech Connect

Research into hadronic interactions and high-energy cosmic rays are closely related. On one hand--due to the indirect observation of cosmic rays through air showers--the understanding of hadronic multiparticle production is needed for deriving the flux and composition of cosmic rays at high energy. On the other hand the highest energy particles from the universe allow us to study the characteristics of hadronic interactions at energies far beyond the reach of terrestrial accelerators. This is the summary of three introductory lectures on our current understanding of hadronic interactions of cosmic rays.

Engel, Ralph [Forschungszentrum Karlsruhe, P.O. Box 3640, 76021 Karlsruhe (Germany); Orellana, Mariana [Instituto Argentino de Radioastronomia (IAR), CCT La Plata (CONICET), C.C.5, 1894 Villa Elisa, Buenos Aires (Argentina); Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque, 1900 La Plata (Argentina); Reynoso, Matias M. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, (7600) Mar del Plata (Argentina); Instituto de Investigaciones Fisicas de Mar del Plata, (UNMdP-CONICET) (Argentina); Vila, Gabriela S. [Instituto Argentino de Radioastronomia (IAR), CCT La Plata (CONICET), C.C.5, 1894 Villa Elisa, Buenos Aires (Argentina)

2009-04-30

120

A hysteresis effect in cosmic ray modulation  

NASA Technical Reports Server (NTRS)

The rigidity dependence is investigated in the modulation of cosmic ray protons and alphas at intermediate (2-13 Gv) rigidities during the declines and recoveries of the cosmic ray flux near cosmic ray minimum. The results include the finding that sudden changes in the modulation of the primary cosmic rays are initiated by large solar particle outflow and begin as type I Forbush decreases. Typically, the modulation spectrum becomes flatter at intermediate rigidity below 13 Gv and steeper at rigidities above 13 Gv during early recovery.

Verschell, H. J.; Mendell, R. B.; Korff, S. A.

1974-01-01

121

Cosmic ray diffusion: Report of the Workshop in Cosmic Ray Diffusion Theory  

NASA Technical Reports Server (NTRS)

A workshop in cosmic ray diffusion theory was held at Goddard Space Flight Center on May 16-17, 1974. Topics discussed and summarized are: (1) cosmic ray measurements as related to diffusion theory; (2) quasi-linear theory, nonlinear theory, and computer simulation of cosmic ray pitch-angle diffusion; and (3) magnetic field fluctuation measurements as related to diffusion theory.

Birmingham, T. J.; Jones, F. C.

1975-01-01

122

Cosmic X-ray physics  

NASA Astrophysics Data System (ADS)

A progress report of research activities carried out in the area of cosmic X-ray physics is presented. The Diffuse X-ray Spectrometer DXS which has been flown twice as a rocket payload is described. The observation times proved to be too small for meaningful X-ray data to be obtained. Data collection and reduction activities from the Ultra-Soft X-ray background (UXT) instrument are described. UXT consists of three mechanically-collimated X-ray gas proportional counters with window/filter combinations which allow measurements in three energy bands, Be (80-110 eV), B (90-187 eV), and O (e84-532 eV). The Be band measurements provide an important constraint on local absorption of X-rays from the hot component of the local interstellar medium. Work has also continued on the development of a calorimetric detector for high-resolution spectroscopy in the 0.1 keV - 8keV energy range.

McCammon, D.; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1985-06-01

123

Cosmic string detection in radio surveys  

NASA Astrophysics Data System (ADS)

We consider the detection of cosmic strings using observations of the anisotropy of the Cosmic Microwave Background. Several methods for detecting cosmic strings are analyzed, using a threshold filter and expansion in orthogonal Haar functions. Computer simulation provides estimates of the noise present in experiments aimed at detection of cosmic strings. Attempts to detect cosmic strings were carried out using the full-sky ILC map obtained as a result of the WMAP space mission. A list of cosmic string candidates has been compiled using the Haar function method.

Sazhina, O. S.; Sementsov, V. N.; Ashimbaeva, N. T.

2014-01-01

124

A balloon-borne ionization spectrometer with very large aperture for the detection of high energy cosmic rays  

NASA Technical Reports Server (NTRS)

A balloon experiment which was used to determine the chemical composition of very high-energy cosmic rays up to and beyond 100 GeV/nucleon is described. The detector had a geometric factor of 1 sq m sr and a total weight on the balloon of 2100 kg. The apparatus consisted of an ionization spectrometer, spark chambers, and plastic scintillation and Cherenkov counters. It was calibrated at CERN up to 24 GeV/c protons and at DESY up to 7 GeV/c electrons. In October 1972 it was flown successfully on a stratospheric balloon.

Atallah, K.; Modlinger, A.; Schmidt, W. K. H.; Cleghorn, T. F.

1975-01-01

125

Cosmic Rays of Extreme Energies  

NASA Astrophysics Data System (ADS)

The origin of the highest energy cosmic rays is a challenging mystery defying decades of observations. The sources of these extremely energetic particles should be among the most powerful extragalactic sources. Extremely energetic cosmic rays (EECRs) reach interaction energies orders of magnitude beyond the LHC probing the frontiers of particle physics. Possible explanations for their origin have narrowed down with the confirmation of a GZK-like spectral feature. Hints of anisotropies in the distribution of arrival directions raise hopes for observing source images directly, however, composition measurements reported by Auger suggest a surprising interpretation. A clear resolution of this mystery calls for much larger statistics at extremely high energies beyond the reach of current observatories. A future space program can achieve several orders of magnitude in additional exposure to EECRs. The first step in such a program is the Extreme Universe Space Observatory at the Japanese Experiment Module (JEM-EUSO). JEM-EUSO is a large field of view ultraviolet telescope to be deployed at the International Space Station. JEM-EUSO can increase the annual exposure to EECRs by an order of magnitude.

Olinto, Angela V.

2013-10-01

126

Early history of cosmic rays at Chicago  

NASA Astrophysics Data System (ADS)

Cosmic ray studies at the University of Chicago were started by Arthur Compton during the late 1920s. The high points of cosmic ray studies at Chicago under Compton and Marcel Schein are the focus of this report, which summarizes the research done at Chicago up to the end of World War II.

Yodh, Gaurang B.

2013-02-01

127

Cosmic-ray detectors on the Moon  

NASA Technical Reports Server (NTRS)

The state of cosmic ray physics is reviewed. It is concluded that the nonexistent lunar magnetic field, the low lunar radiation background, and the lack of an atmosphere on the Moon provide an excellent environment for the study of high energy primary cosmic rays.

Linsley, John

1988-01-01

128

The Discovery and Nature of Cosmic Rays  

NSDL National Science Digital Library

In this lesson, students will learn how cosmic rays were discovered and what they are - including their size and speed. Includes background information for the teacher, questions, activities and information about student preconceptions. This is lesson 1 of 4 from "The Cosmic Ray Telescope for the Effects of Radiation (CRaTER)."

129

Cosmic-ray propagation and containment  

NASA Technical Reports Server (NTRS)

The cosmic rays are an active gaseous component of the disk of the galaxy, and their propagation and containment is a part of the general dynamics of the disk. The sources of cosmic rays are a matter of speculation. The disk is inflated by the cosmic-ray gas pressure, P, comparable to the magnetic pressure B super 2/ 8 pi, but the rate of inflation is unknown. The time spent by the individual cosmic-ray particles in the disk is inversely proportional to the cosmic-ray production rate and may be anything from 100,000 to more than 10 million years. It is evident from the decay of Be(10) that the cosmic rays circulate through a volume of space perhaps ten times the thickness of the gaseous disk, suggesting a magnetic halo extending out approximately 1 kpc from either face of the disk. The cosmic rays may be responsible for the halo by inflating the magnetic fields of the disk. Extension of the fields to 1 kpc would imply a high production rate and short life of cosmic rays in the dense gaseous disk of the galaxy.

Parker, E. N.

1977-01-01

130

Early cosmic ray research in France  

NASA Astrophysics Data System (ADS)

The French research on cosmic rays in the first half of the 20th century is summarized. The main experiments are described as the discovery of air cosmic ray showers by Pierre Auger. The results obtained at the French altitude laboratories like the ``Pic du Midi de Bigorre'' are also briefly presented.

Ravel, Olivier

2013-02-01

131

History of cosmic ray research in Finland  

NASA Astrophysics Data System (ADS)

The history of cosmic ray research in Finland can be traced back to the end of 1950s, when first ground-based cosmic ray measurements started in Turku. The first cosmic ray station was founded in Oulu in 1964 performing measurements of cosmic rays by a muon telescope, which was later complemented by a neutron monitor. Since the 1990s, several research centers and universities, such as The Finnish Meteorological Institute, Helsinki University of Technology, University of Oulu, University of Turku and University of Helsinki have been involved in space science projects, such as SOHO, AMS, Cluster, Cassini, BepiColombo, etc. At the same time, ground-based cosmic ray measurements have reached a new level, including a fully automatic on-line database in Oulu and a new muon measuring underground site in Pyhäsalmi. Research groups in Helsinki, Oulu and Turku have also extensive experience in theoretical investigations of different aspects of cosmic ray physics. Cosmic ray research has a 50-year long history in Finland, covering a wide range from basic long-running ground-based observations to high-technology space-borne instrumentation and sophisticated theoretical studies. Several generations of researchers have been involved in the study ensuring transfer of experience and building the recognized Finnish research school of cosmic ray studies.

Usoskin, I. G.; Valtonen, E.; Vainio, R.; Tanskanen, P. J.; Aurela, A. M.

2009-11-01

132

The Corpuscular Explanation of Cosmic Rays  

Microsoft Academic Search

WITH reference to the attempts that are being made to determine whether the cosmic radiations are corpuscular or undulatory in character, such as those described by Bruno Rossi,1 there is one point which I have vainly tried to understand. Why is it assumed that such rays would or could have the high penetrating power of cosmic rays? As I tried

Frederick Soddy

1931-01-01

133

Thermal Emission from Cosmic Ray Modified Shocks  

NASA Astrophysics Data System (ADS)

Efficient cosmic ray acceleration in supernova remnants results in both higher shock compression and lower post shock temperatures compared to cases where cosmic ray production is ignored. These changes in the properties of the shocked plasma will translate into changes in the thermal X-ray emission in the interaction region between the forward and reverse shocks. Furthermore, the relativistic cosmic ray electrons produced in the diffusive shock acceleration process generate nonthermal X-ray synchrotron emission which is self-consistently determined with the thermal emission through the nonlinear shock acceleration mechanism. We present results from simulations where the remnant hydrodynamics are coupled to efficient cosmic ray acceleration and to a nonequilibrium ionization calculation of thermal X-ray emission. By varying the particle injection efficiency, ambient density, and the electron heating mechanism, we produce a grid of models which show variations in the resultant X-ray spectra where the thermal and nonthermal contributions are determined self-consistently.

Patnaude, Daniel

2007-05-01

134

High energy physics in cosmic rays  

NASA Astrophysics Data System (ADS)

In the first half-century of cosmic ray physics, the primary research focus was on elementary particles; the positron, pi-mesons, mu-mesons, and hyperons were discovered in cosmic rays. Much of this research was carried out at mountain elevations; Pic du Midi in the Pyrenees, Mt. Chacaltaya in Bolivia, and Mt. Evans/Echo Lake in Colorado, among other sites. In the 1960s, claims of the observation of free quarks, and satellite measurements of a significant rise in p-p cross sections, plus the delay in initiating accelerator construction programs for energies above 100 GeV, motivated the Michigan-Wisconsin group to undertake a serious cosmic ray program at Echo Lake. Subsequently, with the succession of higher energy accelerators and colliders at CERN and Fermilab, cosmic ray research has increasingly focused on cosmology and astrophysics, although some groups continue to study cosmic ray particle interactions in emulsion chambers.

Jones, Lawrence W.

2013-02-01

135

Cosmic ray fluxes and atmospheric electricity  

NASA Astrophysics Data System (ADS)

Cosmic rays are the main source of ions in the lower part of the middle atmosphere at the altitudes up to 50-60 km. So, they play very important role in the atmospheric electrical processes. The following questions are discussed: 1). Cosmic ray ion production and ion recombination. It is shown that the equation of ion balance has linear form rather than quadratic one (in the case of ion production by cosmic rays). The rate of ion production and the coefficient of the linear recomb ination of light ions vs. altitude are calculated. 2). The role of cosmic rays in the processes of thundercloud electricity formation and lightning discharges. 3). The cosmic ray variations and their influence of on thunderstorm activity and the global electric circuit operation.

Stozhkov, Y.; Ermakov, V.

136

High energy physics in cosmic rays  

SciTech Connect

In the first half-century of cosmic ray physics, the primary research focus was on elementary particles; the positron, pi-mesons, mu-mesons, and hyperons were discovered in cosmic rays. Much of this research was carried out at mountain elevations; Pic du Midi in the Pyrenees, Mt. Chacaltaya in Bolivia, and Mt. Evans/Echo Lake in Colorado, among other sites. In the 1960s, claims of the observation of free quarks, and satellite measurements of a significant rise in p-p cross sections, plus the delay in initiating accelerator construction programs for energies above 100 GeV, motivated the Michigan-Wisconsin group to undertake a serious cosmic ray program at Echo Lake. Subsequently, with the succession of higher energy accelerators and colliders at CERN and Fermilab, cosmic ray research has increasingly focused on cosmology and astrophysics, although some groups continue to study cosmic ray particle interactions in emulsion chambers.

Jones, Lawrence W. [University of Michigan, Ann Arbor, Michigan (United States)

2013-02-07

137

Research in cosmic and gamma ray astrophysics  

NASA Technical Reports Server (NTRS)

Research activities in cosmic rays, gamma rays, and astrophysical plasmas are covered. The activities are divided into sections and described, followed by a bibliography. The astrophysical aspects of cosmic rays, gamma rays, and of the radiation and electromagnetic field environment of the Earth and other planets are investigated. These investigations are performed by means of energetic particle and photon detector systems flown on spacecraft and balloons.

Stone, E. C.; Davis, L., Jr.; Mewaldt, R. A.; Prince, T. A.

1989-01-01

138

Cosmic Connections:. from Cosmic Rays to Gamma Rays, Cosmic Backgrounds and Magnetic Fields  

NASA Astrophysics Data System (ADS)

Combined data from gamma-ray telescopes and cosmic-ray detectors have produced some new surprising insights regarding intergalactic and galactic magnetic fields, as well as extragalactic background light. We review some recent advances, including a theory explaining the hard spectra of distant blazars and the measurements of intergalactic magnetic fields based on the spectra of distant sources. Furthermore, we discuss the possible contribution of transient galactic sources, such as past gamma-ray bursts and hypernova explosions in the Milky Way, to the observed ux of ultrahigh-energy cosmicrays nuclei. The need for a holistic treatment of gamma rays, cosmic rays, and magnetic fields serves as a unifying theme for these seemingly unrelated phenomena.

Kusenko, Alexander

2013-12-01

139

The Voyager Cosmic Ray Experiment  

NASA Technical Reports Server (NTRS)

The Voyager Cosmic Ray Experiment includes seven dE/dx-E telescopes to measure the energy and charge of particles with atomic numbers from 1 to 26 in the energy range 1-500 MeV/nucleon and to measure electron energy in the range from 3 to 110 MeV. Isotopic composition of hydrogen through sulfur in the range up to 75 Mev/nucleon can also be resolved. The electronic systems include a dual-gain, charge sensitive preamplifier, 4096-channel pulse height analyzers for three parameter analysis of selected events, and an event type readout polling scheme to maximize the use of available telemetry space and to enhance the occurrence of rare events in the data. Details of the detector, electronic and mechanical design are presented.

Stilwell, D. E.; Davis, W. D.; Joyce, R. M.; Mcdonald, F. B.; Trainor, J. H.; Althouse, W. E.; Cummings, A. C.; Garrard, T. L.; Stone, E. C.; Vogt, R. E.

1979-01-01

140

SLAC Cosmic Ray Telescope Facility  

SciTech Connect

SLAC does not have a test beam for the HEP detector development at present. We have therefore created a cosmic ray telescope (CRT) facility, which is presently being used to test the FDIRC prototype. We have used it in the past to debug this prototype with the original SLAC electronics before going to the ESA test beam. Presently, it is used to test a new waveform digitizing electronics developed by the University of Hawaii, and we are also planning to incorporate the new Orsay TDC/ADC electronics. As a next step, we plan to put in a full size DIRC bar box with a new focusing optics, and test it together with a final SuberB electronics. The CRT is located in building 121 at SLAC. We anticipate more users to join in the future. This purpose of this note is to provide an introductory manual for newcomers.

Va'vra, J.

2010-02-15

141

Isotopes in galactic cosmic rays  

NASA Astrophysics Data System (ADS)

Four possible scenarios for the origin of the isotopic ratio of neon in galactic cosmic rays (GCR), (which differs from the solar system ratio), are discussed. The observed compositional effects may actually represent biases in the acceleration. Selective acceleration effects for neon exist either in the solar wind or in solar flares, and extreme variations for helium are seen in solar flares. The abundance of Ne-22 could be explained as due to small star nucleosynthesis, but the absence of N increase between the birth of the sun and now argues against this. The idea that supernovae are contributing fresh material to the GCR has little evidential support. More plausible is the notion that CGR, including the excess Ne-22, could be an outflow from OB star assemblages, including WR stars. The latter have lost their atmospheres through Roche lobe overflow, exposing the surface rich in nucleosynthetic products. These are blown away by the powerful stellar wind.

Reeves, H.

142

Measuring Cosmic Rays at 1 PeV and Above  

NASA Astrophysics Data System (ADS)

High energy cosmic rays arrive at Earth's upper atmosphere from all directions with a remarkably smooth power-law spectrum. Structures in this otherwise smooth spectrum (such as changes in slope or in chemical composition) give clues as to the sources, acceleration, and propagation of these particles. At energies beyond 1 PeV, as cosmic rays become too rare for direct measurements to be practical, large ground-based experiments make indirect measurements of cosmic ray air showers. They employ a wide range of detection technologies and techniques, exploring known features in the spectrum such as the "knee" and the "ankle", as well as searching for new clues in the energy spectrum, chemical composition, and anisotropy in arrival directions of these particles. This talk will overview the broad landscape of ground-based cosmic ray detector arrays, and will focus on the IceCube Observatory at the South Pole.

Rawlins, Katherine

2012-05-01

143

Radio Detection of Cosmic Particles with LOFAR  

NASA Astrophysics Data System (ADS)

Ultra-high energy cosmic rays (UHECRs) have been detected up to energies around 10^20 eV, but their nature is still debated. Once an UHECR hits the Earth atmosphere, a shower of secondary particles is created, rushes though the geomagnetic field, and produces a bright radio flash for some tens of nanoseconds. The LOPES (LOFAR Prototype Station) already detected this emission and showed that radio is a good tracer of particle energy. Models of the emission suggest that radio is also a potentially good tracer of particle composition. As a consequence, the new LOFAR radio telescope has UHECRs detection built in: All 2500 individual antenna elements in LOFAR come with a memory ring buffer (Transient Buffer Board, TBB) and real-time pulse detections, allowing particles above 10^17 eV to be detected. Moreover, a small particle detector array, LORA (LOFAR-Radboud Airshower array), provides cross-calibration and external triggers when desired. Using first commissioning data, the radio emission of UHECRs has been detected with exquisite detail, providing new insight into the emission process. The TBBs can also be used to search for sub-second astrophysical transients such as giant pulses from pulsars, stellar and planetary flares, cosmic ray impacts on the moon, and other exotic events.

Falcke, Heino

2012-01-01

144

Cosmic ray propagation in the local superbubble  

NASA Technical Reports Server (NTRS)

It is suggested that a ring of HI gas lying in the galactic plane is part of a supershell which formed some 3 x to the 7th power years ago. The consequences of a closed magnetic supershell for cosmic ray propagation are examined and it is concluded that there is no evidence which precludes the production and trapping of cosmic rays in such a region. A consequence of superbubble confinement is that the mean age of cosmic rays would be independent of energy. This can be tested by high energy observations of the isotopic composition of Be.

Steitmatter, R. E.; Balasubrahmanyan, V. K.; Protheroe, R. J.; Ormes, J. F.

1984-01-01

145

Galactic cosmic ray flux simulation and prediction.  

PubMed

A dynamic galactic cosmic ray model is proposed to quantitatively describe the z=1-28 ions and electrons of E=10-10(5) MeV/nucleon and their particle flux variations around the Earth's orbit and beyond the Earth's magnetosphere due to diverse large-scale variations of solar activity factors. The variations of large-scale heliospheric magnetic fields and the galactic cosmic ray flux variation time delays relative to solar activity variations are simulated. The lag characteristics and sunspot number predictions having been determined in detail, the model can be used to predict galactic cosmic ray flux levels. PMID:11540366

Nymmik, R A; Panasyuk, M I; Suslov, A A

1996-01-01

146

High-Energy cosmic rays and neutrinos from gamma-ray bursts  

NASA Astrophysics Data System (ADS)

A complete model for the origin of high-energy ( 1014 eV) cosmic rays from gamma-ray bursts (GRBs) and implications of this hypothesis are described. Detection of high-energy neutrinos from GRBs provide an unambiguous test of the model. Evidence for cosmic-ray acceleration in GRBs is suggested by the detection of anomalous ?-ray components such as that observed from GRB 941017. Neutron ?-decay halos around star-forming galaxies such as the Milky Way are formed as a consequence of this model. Cosmic rays from GRBs in the Galaxy are unlikely to account for the ˜ 1018 eV cosmic-ray excess reported by the Sydney University Giant Air Shower Recorder (SUGAR), but could contribute to past extinction events.

Dermer, C.

2005-07-01

147

Consistency of cosmic-ray source abudances with explosive nucleosynthesis  

NASA Technical Reports Server (NTRS)

A model was examined in which the cosmic ray abundances of elements from C to Fe are consistent with explosive nucleosynthesis. The observed abundance of cosmic rays near the earth, cosmic ray source abundance, and solar system abundance are discussed along with the ratios of cosmic ray sources to the solar system abundances.

Kozlovsky, B.; Ramaty, R.

1973-01-01

148

Cosmic Rays in the Earth'S Magnetic Field.  

National Technical Information Service (NTIS)

Studies are presented of the behavior of cosmic rays in the earth's magnetic field. It discusses the theory of motion of charged particles in an idealized field model and presents results of trajectory calculations of asymptotic directions and cutoff rigi...

L. I. Dorman V. S. Smirnov M. I. Tyasto

1973-01-01

149

Detector requirements for a cosmic ray muon scattering tomography system  

Microsoft Academic Search

Cosmic ray muon scattering tomography is one of four techniques currently being investigated at AWE for the detection of special nuclear material (SNM). In order to develop a prototype muon detection system, it is necessary to consider the requirements of the radiation detectors with respect to; coincidence timing for system triggering; tracking of the muon trajectory; and determination of muon

Lindsay Cox; Peter Adsley; John O'Malley; Steve Quillin; Chris Steer; Ceri Clemett

2008-01-01

150

The origin of ultrahigh energy cosmic rays.  

NASA Astrophysics Data System (ADS)

The authors have studied cosmic rays (CR) of energy above 1019eV using data published by the World Data Centre C2 for cosmic rays. Three catalogues are available that contain information from four large CR experiments at Volcano Ranch, Haverah Park, SUGAR (Sydney), and Yakutsk, respectively. The data have been summed to study the sky as seen in the most energetic particles.

Chi, X.; Szabelski, J.; Vahia, M. N.; Wolfendale, A. W.

151

Cosmic ray test of INO RPC stack  

NASA Astrophysics Data System (ADS)

The India-based Neutrino Observatory (INO) collaboration is planning to build a 50 kt magnetised iron calorimeter (ICAL) detector using glass Resistive Plate Chambers (RPCs) as active detector elements. A stack of 12 such glass RPCs of 1 m ×1 m in area is tracking cosmic ray muons for over three years. In this paper, we will review the constructional aspects of the stack and discuss the performance of the RPCs using this cosmic ray data.

Bhuyan, M.; Datar, V. M.; Kalmani, S. D.; Lahamge, S. M.; Mondal, N. K.; Nagaraj, P.; Pal, S.; Reddy, L. V.; Redij, A.; Samuel, D.; Saraf, M. N.; Satyanarayana, B.; Shinde, R. R.; Verma, P.

2012-01-01

152

Cosmic Ray Astrophysics with AMS-02  

NASA Astrophysics Data System (ADS)

The Alpha Magnetic Spectrometer (AMS) is a cosmic ray (CR) experiment that will operate on the International Space Station for three years, measuring the particle spectra in the rigidity range from 0.2 GV to 2 TV. The AMS-02 detector will provide measurements with unprecedented statistics of the hadronic and leptonic cosmic rays, allowing for a better study of the Earth magnetosphere, of the solar system environment, of the solar system neighborhood, and of the galactic interstellar medium.

Casadei, Diego

2005-04-01

153

Apollo 17 lunar surface cosmic ray detector  

NASA Technical Reports Server (NTRS)

The objectives and selected data are presented for the Apollo 17 Lunar Surface Cosmic Ray Experiment (LSCRE) for the purpose of introducing an analysis of three of the separate detectors contained within in LSCRE package. The mica detector for measuring heavy solar wind, and the lexan stack and glass detectors for measuring energetic particles in space are discussed in terms of their deployment, exposure time, calibration, and data yield. Relevant articles on solar particles, interplanetary ions, and cosmic ray nuclei are also included.

Walker, R. M.

1974-01-01

154

EDITORIAL: Focus on High Energy Cosmic Rays FOCUS ON HIGH ENERGY COSMIC RAYS  

NASA Astrophysics Data System (ADS)

The topic of high-energy cosmic rays has recently attracted significant attention. While the AGASA and HiRes Observatories have closed after many years of successful operation, the Pierre Auger Observatory began taking data in January 2004 and the first results have been reported. Plans for the next generation of instruments are in hand: funding is now being sought for the northern phase of the Auger Observatory and plans for a space detector, JEM-EUSO, to be launched in 2013-14 are well advanced with the long-term target of a dedicated satellite for the 2020s. It therefore seemed an appropriate time to make a collection of outstanding and original research articles from the leading experimental groups and from some of the theorists who seek to interpret the hard-won data and to speculate on the origin of the highest energy cosmic rays. This focus issue in New Journal of Physics on the topic of high energy cosmic rays, contains a comprehensive account of the work of the Yakutsk group (A A Ivanov, S P Knurenko and I Ye Sleptsov) who have used Cerenkov radiation produced by shower particles in the air to provide the basis for energy calibration. This technique contrasts with that of detecting fluorescence radiation from space that is proposed for the JEM-EUSO instrument to be placed on the International Space Station in 2013, described by Y Takahashi. Supplementing this is an article by A Santangelo and A Petrolini describing the scientific goals, requirements and main instrument features of the Super Extreme Universe Space Observatory mission (S-EUSO). The use of fluorescence light to measure energies was the key component of the HiRes instrument and is also used extensively by the Pierre Auger Collaboration so an article, by F Arqueros, F Blanco and J Rosado, summarizing the properties of fluorescence emission, still not fully understood, is timely. M Nagano, one of the architects of the AGASA Observatory, has provided an overview of the experimental situation with regard to the energy spectrum of the highest energy cosmic rays. The remaining contributions are of a more theoretical nature and discuss propagation (T Stanev), the time structure of multi-messenger signals (G H W Sigl), ultra-high energy cosmic ray production near black holes (A Yu Neronov, D V Semikoz and I I Tkachev), production in jets associated with black holes (C D Dermer, S Razzaque, J Finke and A Atoyan) and emission from a specific object, Cen A (M Kachelriess, S S Ostapchenko and R Tomas). Additionally the potential of high energy cosmic rays to give information about features of hadronic interactions, specifically the cross-section for p-air collisions, is discussed in the paper by R Ulrich et al. We thank all our authors most sincerely for their efforts and Tim Smith and his editorial team for their hard work. We believe that this collection of articles will be of great value to workers in the field: further contributions to this focus issue will be published during the course of 2009. Focus on High Energy Cosmic Rays Contents The cosmic ray energy spectrum as measured using the Pierre Auger Observatory Giorgio Matthiae The northern site of the Pierre Auger Observatory Johannes Blümer and the Pierre Auger Collaboration Searching for new physics with ultrahigh energy cosmic rays Floyd W Stecker and Sean T Scully On the measurement of the proton-air cross section using air shower data R Ulrich, J Blümer, R Engel, F Schüssler and M Unger High energy radiation from Centaurus A M Kachelrieß, S Ostapchenko and R Tomàs Ultra-high-energy cosmic rays from black hole jets of radio galaxies C D Dermer, S Razzaque, J D Finke and A Atoyan Ultra-high energy cosmic ray production in the polar cap regions of black hole magnetospheres A Yu Neronov, D V Semikoz and I I Tkachev Time structure and multi-messenger signatures of ultra-high energy cosmic ray sources Günter Sigl Propagation of ultrahigh-energy cosmic rays Todor Stanev Search for the end of the energy spectrum of primary cosmic rays M Nagano Analysis of the fluorescence emission from atmospheric ni

Teshima, Masahiro; Watson, Alan A.

2009-06-01

155

Cosmic-ray Helium Hardening  

NASA Astrophysics Data System (ADS)

Recent observations by the CREAM and ATIC-2 experiments suggest that (1) the spectrum of cosmic-ray (CR) helium is harder than that of CR protons below the knee energy, 1015eV, and (2) all CR spectra become hard at gsim1011eV nucleon-1. We propose a new idea, that higher energy CRs are generated in a more helium-rich region, to explain the hardening without introducing different sources for CR helium. The helium-to-proton ratio at ~100 TeV exceeds the Big Bang abundance Y = 0.25 by several times, and the different spectrum is not reproduced within the diffusive shock acceleration theory. We argue that CRs are produced in a chemically enriched region, such as a superbubble, and the outward-decreasing abundance naturally leads to the hard spectrum of CR helium if CRs escape from the supernova remnant shock in an energy-dependent way. We provide a simple analytical spectrum that also fits well the hardening due to the decreasing Mach number in the hot superbubble with ~106 K. Our model predicts hard and concave spectra for heavier CR elements.

Ohira, Yutaka; Ioka, Kunihito

2011-03-01

156

Cosmic ray studies with the MINOS detectors  

NASA Astrophysics Data System (ADS)

The MINOS experiment uses two layered scintillator and steel detectors along with a muon neutrino beam to search for ?? disappearance, and thus neutrino oscillations. The Far Detector ('FD') is situated in a former iron mine in the Soudan Underground Mine State Park in Northeastern MN, 700 m (2070 mwe) below the surface. This 5.4 kt steel/scintillator calorimeter measures the neutrino flux after they have traveled the 735 km baseline. It also detects atmospheric neutrinos at a rate of several per week, and is the first magnetized atmospheric neutrino detector, able to discriminate between ?? and ?? on an event-by-event basis. The similar 1 kt Near Detector ('ND') is 100 m (220 mwe) underground at Fermilab. This poster discusses the science being done with the high energy cosmic ray muons which penetrate the rock overburden and are seen by the detectors. The typical surface energy of those seen at the FD are ~1 TeV (coming from ~8 TeV primary cosmic rays) and ~110 GeV at the ND (~900 GeV primaries).

Habig, Alec; Minos Collaboration

2008-11-01

157

Cosmic ray acceleration in young supernova remnants  

NASA Astrophysics Data System (ADS)

We investigate the appearance of magnetic field amplification resulting from a cosmic ray escape current in the context of supernova remnant shock waves. The current is inversely proportional to the maximum energy of cosmic rays, and is a strong function of the shock velocity. Depending on the evolution of the shock wave, which is drastically different for different circumstellar environments, the maximum energy of cosmic rays as required to generate enough current to trigger the non-resonant hybrid instability that confines the cosmic rays follows a different evolution and reaches different values. We find that the best candidates to accelerate cosmic rays to ˜ few PeV energies are young remnants in a dense environment, such as a red supergiant wind, as may be applicable to Cassiopeia A. We also find that for a typical background magnetic field strength of 5 ?G the instability is quenched in about 1000 years, making SN1006 just at the border of candidates for cosmic ray acceleration to high energies.

Schure, K. M.; Bell, A. R.

2013-10-01

158

Multi-spectra Cosmic Ray Flux Measurement  

NASA Astrophysics Data System (ADS)

The Earth's upper atmosphere is constantly bombarded by rain of charged particles known as primary cosmic rays. These primary cosmic rays will collide with the atmospheric molecules and create extensive secondary particles which shower downward to the surface of the Earth. In recent years, a few studies have been done regarding to the applications of the cosmic ray measurements and the correlations between the Earth's climate conditions and the cosmic ray fluxes [1,2,3]. Most of the particles, which reach to the surface of the Earth, are muons together with a small percentage of electrons, gammas, neutrons, etc. At Georgia State University, multiple cosmic ray particle detectors have been constructed to measure the fluxes and energy distributions of the secondary cosmic ray particles. In this presentation, we will briefly describe these prototype detectors and show the preliminary test results. Reference: [1] K.Borozdin, G.Hogan, C.Morris, W.Priedhorsky, A.Saunders, L.Shultz, M.Teasdale, Nature, Vol.422, 277 (2003). [2] L.V. Egorova, V. Ya Vovk, O.A. Troshichev, Journal of Atmospheric and Terrestrial Physics 62, 955-966 (2000). [3] Henrik Svensmark, Phy. Rev. Lett. 81, 5027 (1998). )

He, Xiaochun; Dayananda, Mathes

2010-02-01

159

Contributions to the 19th International Cosmic Ray Conference  

NASA Technical Reports Server (NTRS)

Various aspects of cosmic radiation, its measurements and their patterns are presented. Measurement techniques and variations in solar cosmic ray patterns and calculations of elemental abundances are reviewed.

1985-01-01

160

Phantom Cosmic Ray Decreases and their Extraterrestrial Origins  

NASA Astrophysics Data System (ADS)

Galactic cosmic rays are extremely high energy charged particles accelerated at extra-solar sources such as supernovae, active galactic nuclei, quasars, and gamma-ray bursts. Upon arrival at Earth's atmosphere, they collide with air molecules to produce a shower of secondary particles. One product of this air shower is energetic neutrons, which can be detected at the Earth's surface. Neutron monitors have been routinely operating for more than half a century and have shown that the cosmic ray flux at the top of the atmosphere is modulated by the heliospheric magnetic field (HMF), both at solar cycle time scales and due to shorter-term HMF variations, such as result from coronal mass ejections (CMEs). When a CME passes over the Earth, the neutron monitor counts are reduced sharply and suddenly (in a matter of hours) due to the modulation of cosmic rays by the enhancement in the heliospheric magnetic field (HMF). Such a drop in neutron counts is known as a Forbush Decrease. We present examples of unusual Forbush Decreases where there is no disturbance in the HMF at Earth at the time, which we name 'Phantom Cosmic Ray Decreases' (PCRDs). For recent PCRD events, we examine STEREO in-situ data and in each case, we find a large CME in either STEREO-A or -B. We also study neutron counts for each event from a number of neutron monitors at different longitudes. Differences between the size of the cosmic ray decreases at different longitudes are shown to give information on the location of the cosmic ray modulation source. We thus propose that these PCRDs are caused by CMEs which have missed Earth but which are large and intense enough to block out galactic cosmic rays on trajectories toward Earth.

Thomas, Simon; Owens, Mathew; Lockwood, Mike; Scott, Chris

2014-05-01

161

Cosmic Ray Acceleration in Astrophysical Environments  

NASA Astrophysics Data System (ADS)

Cosmic ray acceleration in astrophysical shocks is important. We discuss these shocks' properties and we perform Monte Carlo simulations studying their efficiency in accelerating particles (i.e. protons or electrons) up to very high energies with an application to astrophysical regions such as Super Novae, Active Galactic Nuclei hot spots and Gamma Ray Bursts. The efficiency of the acceleration mechanism at shocks varies in regard to the inclination of the magnetic field to the shock normal (e.g. subluminal shocks, superluminal shocks). This fact could have consequences to the contribution of the very high energy cosmic rays to the observed cosmic ray spectrum and the relevant neutrino and gamma-ray emission.

Meli, A.; Mastichiadis, A.

2008-01-01

162

Gamma-rays from cosmic ray interactions in supernova shells  

NASA Technical Reports Server (NTRS)

A model is presented for the transport and interaction of cosmic rays accelerated by a pulsar and confined inside an expanding supernova remnant. Assuming that protons are accelerated at the reverse shock in the confined pulsar wind and convected into the shell via the Rayleigh-Taylor instability, the diffusion and interaction of these protons in the expanding envelope is modeled. The resulting gamma-ray flux is lower than previous estimates due primarily to the inclusion of proton adiabatic losses in the expanding pulsar wind. Energy-dependent diffusion causes the higher energy gamma-ray light curves to decay faster than those at lower energy. The predicted flux from SN1987A, for proton luminosity less than 10 exp 40 erg/s, is below the present detector sensitivities at both GeV and TeV energies, although supernovae occurring within the Galaxy may be detectable.

Harding, A. K.; Mastichiadis, A.; Protheroe, R. J.; Szabo, A. P.

1991-01-01

163

Cosmic rays from the Geminga supernova  

NASA Astrophysics Data System (ADS)

The bright gamma-ray source Geminga has puzzled astronomers for twenty years, because of its lack of emission outside the gamma-ray regime. Recently, the nature of this object has finally been established with the discovery of a 237 ms pulsar in soft X-ray data (Halpern and Holt, 1992, Nature, 357, 222). The measurement of pulsations between 1975 and 1992 yields a steady spin-down consistent with that of an isolated pulsar, with a characteristic age of tau = 3.7 x 105 years (Bignami and Caraveo, 1992, Nature, 357, 287). From the observed gamma-ray flux, the absolute upper limit on the distance is put at R less than 380 pc, but a Vela-like gamma-ray efficiency reduces the estimate to more like R approximately 40 pc. This suggests that Geminga is one of the closest pulsars known and the existence of this neutron star implies that a supernova exploded a few 105 years ago. This explains the current soft X-ray background (Cox and Anderson, 1982, Astrophys. J., 253, 268), and it has also recently been suggested that this nearby cataclysm may be responsible for the local bubble in the Interstellar Medium (Gehrels and Chen, 1993, Nature, 361, 706; Hajivassiliou, 1992, Nature, 355, 232). Young supernova remnants are thought to be capable of efficiently accelerating cosmic rays up to 105 GeV (Lagage and Cesarsky, 1983, Astron. Astrophys., 125, 249), and if this is the case, the contribution to the ambient cosmic ray intensity from the Geminga remnant must be very important, given its proximity to Earth. Here, we assume acceleration and subsequent diffusion from the remnant, and find that both the expected cosmic ray flux and its anisotropy are close to those observed just below the 'knee' in the cosmic ray spectrum. The conventional view, of course, is that cosmic rays permeate the whole of the Galaxy, but there is evidence to suggest that the cosmic rays we obseve are of relatively local origin. This has been used (Streitmatter et al., 1985, Astron. Astrophys., 143, 249) to suggest that cosmic rays are trapped by a local magnetic supershell, and no evidence from composition or anisotropy measurements was found which precluded the production and trapping of cosmic rays in such a region.

Johnson, P. A.

1994-04-01

164

Cascaded Gamma Rays as a Probe of Cosmic Rays  

NASA Astrophysics Data System (ADS)

Very-high-energy (VHE) and ultra-high-energy (UHE) gamma rays from extragalactic sources experience electromagnetic cascades during their propagation in intergalactic space. Recent gamma-ray data on TeV blazars and the diffuse gamma-ray background may have hints of the cascade emission, which are especially interesting if it comes from UHE cosmic rays. I show that cosmic-ray-induced cascades can be discriminated from gamma-ray-induced cascades with detailed gamma-ray spectra. I also discuss roles of structured magnetic fields, which suppress inverse-Compton pair halos/echoes but lead to guaranteed signals - synchrotron pair halos/echoes.

Murase, Kohta

2014-06-01

165

Diffuse Galactic gamma rays from shock-accelerated cosmic rays.  

PubMed

A shock-accelerated particle flux is proportional to p(-s), where p is the particle momentum, follows from simple theoretical considerations of cosmic-ray acceleration at nonrelativistic shocks followed by rigidity-dependent escape into the Galactic halo. A flux of shock-accelerated cosmic-ray protons with s?2.8 provides an adequate fit to the Fermi Large Area Telescope ?-ray emission spectra of high-latitude and molecular cloud gas when uncertainties in nuclear production models are considered. A break in the spectrum of cosmic-ray protons claimed by Neronov, Semikoz, and Taylor [Phys. Rev. Lett. 108, 051105 (2012)] when fitting the ?-ray spectra of high-latitude molecular clouds is a consequence of using a cosmic-ray proton flux described by a power law in kinetic energy. PMID:23002818

Dermer, Charles D

2012-08-31

166

The galactic cosmic ray ionization rate  

PubMed Central

The chemistry that occurs in the interstellar medium in response to cosmic ray ionization is summarized, and a review of the ionization rates that have been derived from measurements of molecular abundances is presented. The successful detection of large abundances of H3+ in diffuse clouds and the recognition that dissociative recombination of H3+ is fast has led to an upward revision of the derived ionization rates. In dense clouds the molecular abundances are sensitive to the depletion of carbon monoxide, atomic oxygen, nitrogen, water, and metals and the presence of large molecules and grains. Measurements of the relative abundances of deuterated species provide information about the ion removal mechanisms, but uncertainties remain. The models, both of dense and diffuse clouds, that are used to interpret the observations may be seriously inadequate. Nevertheless, it appears that the ionization rates differ in dense and diffuse clouds and in the intercloud medium.

Dalgarno, A.

2006-01-01

167

Cosmic-ray ionization and chemistry: observations.  

NASA Astrophysics Data System (ADS)

The interaction between cosmic-rays and the dense regions of the ISM has important consequences on the physical and chemical state of the ISM. A major consequence is the ionisation of the ISM. I review here how the cosmic rays ionisation rate zeta is measured in the ISM and the values so far measured in ``average'' galactic clouds. I then discuss new observations in the direction of clouds spatially associated with bright gamma -rays TeV sources. The TeV emission is believed to be caused by the decay of pi 0 pions created by the irradiation of molecular clouds by large fluxes of cosmic rays just produced in SNRs. The measured zeta , enhanced by a factor 100 in at least one case, confirms this hypothesis. In addition, the high zeta causes a peculiar chemistry with the cloud possessing regions in Low and High Ionisation Phases (called LIP and HIP, in the literature), also briefly reviewed in this contribution.

Ceccarelli, C.

168

Cosmic Ray Nuclei (CRN) detector investigation  

NASA Technical Reports Server (NTRS)

The Cosmic Ray Nuclei (CRN) detector was designed to measure elemental composition and energy spectra of cosmic radiation nuclei ranging from lithium to iron. CRN was flown as part of Spacelab 2 in 1985, and consisted of three basic components: a gas Cerenkov counter, a transition radiation detector, and plastic scintillators. The results of the experiment indicate that the relative abundance of elements in this range, traveling at near relativistic velocities, is similar to those reported at lower energy.

Meyer, Peter; Muller, Dietrich; Lheureux, Jacques; Swordy, Simon

1991-01-01

169

High Energy Cosmic Electrons: Messengers from Nearby Cosmic Ray Sources or Dark Matter?  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the recent discoveries by the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-Ray Telescope in reference to high energy cosmic electrons, and whether their source is cosmic rays or dark matter. Specific interest is devoted to Cosmic Ray electrons anisotropy,

Moiseev, Alexander

2011-01-01

170

Detecting a mass change inside a volcano by cosmic-ray muon radiography (muography): First results from measurements at Asama volcano, Japan  

NASA Astrophysics Data System (ADS)

A visual detection and monitoring of volcanic eruptions is the most essential information. In February 2, 2009, Asama volcano, Japan erupted and a large amount of volcanic ash was ejected from the vent. We have observed the activity at Asama since October 12, 2008. For eruption monitoring we used cosmic-ray muon radiography (muography), a new volcano monitoring system recently developed by Tanaka et al. (2009). We measured a quantitative mass loss inside the crater during the eruption event although no changes were found below the crater. The measured value of 30,780 tons is consistent with a model calculation of volcanic ash flow as observed on February 2, 2009. The obtained radiographic image suggests that a “boiling liquid expanding vapor explosion” occurred and a part of an old lava mound was exploded. This picture is consistent with the analytical result of the volcanic ash ejected on February 2, 2009.

Tanaka, Hiroyuki K. M.; Uchida, Tomihisa; Tanaka, Manobu; Takeo, Minoru; Oikawa, Jun; Ohminato, Takao; Aoki, Yosuke; Koyama, Etsuro; Tsuji, Hiroshi

2009-09-01

171

Cosmic-ray hydrodynamics at relativistic shocks  

NASA Technical Reports Server (NTRS)

A test particle description of first-order Fermi acceleration of cosmic rays at plane-parallel relativistic shocks is presented in which the pitch angle distribution is obtained explicitly and used to determine the pressure anisotropy or variable Eddington factor as a function of position. The Eddington factor is in turn used to find the hydrodynamical cosmic-ray sound speed, taking the anisotropy into account. For upstream flows speeds above c/sq rt 3, it is shown that the cosmic-ray sound speed exceeds the shock speed in a region just upstream of the shock and decreases montonically with distance further upstream, reaching the value c/sq rt 3 far from the shock. Thus, the shock succeeds in maintaining an anisotropy in the cosmic-ray distribution which is sufficient to keep the flow subsonic with respect to the cosmic-ray sound speed both downstream and in a finite region upstream. The astrophysical implications of these findings are discussed.

Kirk, J. G.; Webb, G. M.

1988-01-01

172

Cosmic ray sun shadow in Soudan 2 underground muon flux  

NASA Astrophysics Data System (ADS)

The absorption of cosmic rays by the sun produces a shadow at the earth. The angular offset and broadening of the shadow are determined by the magnitude and structure of the interplanetary magnetic field (IPMF) in the inner solar system. The authors report the first measurement of the solar cosmic ray shadow by detection of deep underground muon flux in observations made during the entire ten-year interval 1989 to 1998. The sun shadow varies significantly during this time, with a 3.3(sigma) shadow observed during the years 1995 to 1998.

Allison, W. W. M.; Alner, G. J.; Ayres, D. S.; Barrett, W. L.; Bode, C.

1999-06-01

173

Some methods in high energy cosmic ray measurement  

NASA Technical Reports Server (NTRS)

Problems concerning ion chamber and emulsion detection techniques for high energy cosmic ray measurement are investigated. The calculation of the average energy actually deposited in an ion chamber by an ultra-high energy particle of large mass and charge is examined. A calculational scheme already applied successfully to particles of charge 1 is extended. Also, the calibration of a plate of plastic scintillator for measurement of the position of a cosmic ray shower passing through it is discussed. The method of calibration is to inject pulses of flight at known positions on the plate and record the responses of photomultiplier tubes at the corner of the plate.

Shand, J. B., Jr.

1980-01-01

174

Cosmic ray sun shadow in Soudan 2 underground muon flux.  

SciTech Connect

The absorption of cosmic rays by the sun produces a shadow at the earth. The angular offset and broadening of the shadow are determined by the magnitude and structure of the interplanetary magnetic field (IPMF) in the inner solar system. The authors report the first measurement of the solar cosmic ray shadow by detection of deep underground muon flux in observations made during the entire ten-year interval 1989 to 1998. The sun shadow varies significantly during this time, with a 3.3{sigma} shadow observed during the years 1995 to 1998.

Allison, W. W. M.; Alner, G. J.; Ayres, D. S.; Barrett, W. L.; Bode, C.; Fields, T. H.; Goodman, M. C.; Joffe-Minor, T.; Price, L. E.; Seidlein, R.; Soudan 2 Collaboration; Thron, J. L.

1999-06-23

175

COSMIC RAY BACKGROUND ANALYSIS FOR A CARGO CONTAINER COUNTER.  

SciTech Connect

We have developed a new model for calculating the expected yield of cosmic-ray spallation neutrons in a Cargo Container Counter, and we have benchmarked the model against measurements made with several existing large neutron counters. We also developed two versions of a new measurement uncertainty prediction code based on Microsoft Excel spreadsheets. The codes calculate the minimum detectability limit for the Cargo Container Counter for either neutron singles or doubles counting, and also propagate the uncertainties associated with efficiency normalization flux monitors and cosmic ray flux monitors. This paper will describe the physics basis for this analysis, and the results obtained for several different counter designs.

Ensslin, Norbert; Geist, W. H. (William H.); Lestone, J. P. (John P.); Mayo, D. R. (Douglas R.); Menlove, Howard O.

2001-01-01

176

A cosmic ray muon detector for astronomy teaching  

Microsoft Academic Search

Practical astronomy is usually taught using optical telescopes or, more rarely, radio telescopes. For a similar cost, complementary studies may be made of astrophysical particles through the use of a modestly sized muon detector. Such a detector records the arrival of cosmic ray particles that have traversed the heliosphere and the rate of muon detections reflects the flux of those

R. W. Clay; Z. Kurban; A. H. Maghrabi; N. R. Wild

2000-01-01

177

Supernova Remnants, Cosmic Rays, and GLAST  

ScienceCinema

The shock waves of supernova remnants (SNRs) are the traditional sources of Galactic cosmic rays, at least up to about 3000 TeV (the "knee" energy in the cosmic-ray spectrum). In the last decade or so, X-ray observations have confirmed in a few SNRs the presence of synchrotron-X-ray-emitting electrons with energies of order 100 TeV. TeV photons from SNRs have been observed with ground-based air Cerenkov telescopes as well, but it is still unclear whether they are due to hadronic processes (inelastic p-p scattering of cosmic-ray protons from thermal gas, with secondary neutral pions decaying to gamma rays), or to leptonic processes (inverse-Compton upscattering of cosmic microwave background photons, or bremsstrahlung). The spatial structure of synchrotron X-rays as observed with the Chandra X-ray Observatory suggests the remarkable possibility that magnetic fields are amplified by orders of magnitude in strong shock waves. The electron spectra inferred from X-rays reach 100 TeV, but at that energy are cutting off steeply, well below the "knee" energy. Are the cutoff processes due only to radiative losses so that ion spectra might continue unsteepened? Can we confirm the presence of energetic ions in SNRs at all? Are typical SNRs capable of supplying the pool of Galactic cosmic rays? Is strong magnetic-field amplification a property of strong astrophysical shocks in general? These major questions require the next generation of observational tools. I shall outline the theoretical and observational framework of particle acceleration to high energies in SNRs, and shall describe how GLAST will advance this field.

178

Cosmic Ray-Air Shower Measurement from Space  

NASA Astrophysics Data System (ADS)

A feasibility study has been initiated to observe from space the highest energy cosmic rays above 1021 eV. A satellite observatory concept, the Maximum-energy Auger (Air)-Shower Satellite (MASS), is recently renamed as the Orbital Wide-angle Collector (OWL) by taking its unique feature of using a very wide field-of-view (FOV) optics. A huge array of imaging devices (about 106 pixels) is required to detect and record fluorescent light profiles of cosmic ray cascades in the atmosphere. The FOV of MASS could extend to as large as about 60 in. diameter, which views (500 - 1000 km) of earth's surface and more than 300 - 1000 cosmic ray events per year could be observed above 1020 eV. From far above the atmosphere, the MASS/OWL satellite should be capable of observing events at all angles including near horizontal tracks, and would have considerable aperture for high energy photon and neutrino observation. With a large aperture and the spatial and temporal resolution, MASS could determine the energy spectrum, the mass composition, and arrival anisotropy of cosmic rays from 1020 eV to 1022 eV; a region hitherto not explored by ground-based detectors such as the Fly's Eye and air-shower arrays. MASS/OWL's ability to identify cosmic neutrinos and gamma rays may help providing evidence for the theory which attributes the above cut-off cosmic ray flux to the decay of topological defects. Very wide FOV optics system of MASS/OWL with a large array of imaging devices is applicable to observe other atmospheric phenomena including upper atmospheric lightning. The wide FOV MASS optics being developed can also improve ground-based gamma-ray observatories by allowing simultaneous observation of many gamma ray sources located at different constellations.

Takahashi, Yoshiyuki

1997-03-01

179

Cosmic Ray-Air Shower Measurement from Space  

NASA Technical Reports Server (NTRS)

A feasibility study has been initiated to observe from space the highest energy cosmic rays above 1021 eV. A satellite observatory concept, the Maximum-energy Auger (Air)-Shower Satellite (MASS), is recently renamed as the Orbital Wide-angle Collector (OWL) by taking its unique feature of using a very wide field-of-view (FOV) optics. A huge array of imaging devices (about 10(exp 6) pixels) is required to detect and record fluorescent light profiles of cosmic ray cascades in the atmosphere. The FOV of MASS could extend to as large as about 60 in. diameter, which views (500 - 1000 km) of earth's surface and more than 300 - 1000 cosmic ray events per year could be observed above 1020 eV. From far above the atmosphere, the MASS/OWL satellite should be capable of observing events at all angles including near horizontal tracks, and would have considerable aperture for high energy photon and neutrino observation. With a large aperture and the spatial and temporal resolution, MASS could determine the energy spectrum, the mass composition, and arrival anisotropy of cosmic rays from 1020 eV to 1022 eV; a region hitherto not explored by ground-based detectors such as the Fly's Eye and air-shower arrays. MASS/OWL's ability to identify cosmic neutrinos and gamma rays may help providing evidence for the theory which attributes the above cut-off cosmic ray flux to the decay of topological defects. Very wide FOV optics system of MASS/OWL with a large array of imaging devices is applicable to observe other atmospheric phenomena including upper atmospheric lightning. The wide FOV MASS optics being developed can also improve ground-based gamma-ray observatories by allowing simultaneous observation of many gamma ray sources located at different constellations.

Takahashi, Yoshiyuki

1997-01-01

180

Cosmic strings and ultra-high energy cosmic rays  

NASA Technical Reports Server (NTRS)

The flux is calculated of ultrahigh energy protons due to the process of cusp evaporation from cosmic string loops. For the standard value of the dimensionless cosmic string parameter epsilon is identical to G(sub mu) approx. = 10(exp -6), the flux is several orders of magnitude below the observed cosmic ray flux of ultrahigh energy protons. However, the flux at any energy initially increases as the value of epsilon is decreased. This at first suggests that there may be a lower limit on the value of epsilon, which would imply a lower limit on the temperature of a cosmic string forming phase transition in the early universe. However, the calculation shows that this is not the case -- the particle flux at any energy reaches its highest value at epsilon approx. = 10(exp -15) and it then decreases for further decrease of the value of epsilon. This is due to the fact that for too small values of epsilon (less than 10(exp -15)), the energy loss of the loops through the cusp evaporation process itself (rather than gravitational energy loss of the loops) becomes the dominant factor that controls the behavior of the number density of the loops at the relevant times of emission of the particles. The highest flux at any energy remains at least four orders of magnitude below the observed flux. There is thus no lower limit on epsilon.

Bhattacharjee, Pijushpani

1989-01-01

181

Positron Abundance in Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

On 2000 August 25 from Lynn Lake, Manitoba, we conducted a balloon flight of the LEE/AESOP (Low Energy Electrons/Anti-Electron Sub Orbital Payload) payload to measure the spectrum of cosmic-ray electrons (resolved into negatrons and positrons) from 500 MeV to 3 GeV. Analysis of the data from that flight reveals a significant decrease in the cosmic-ray positron abundance from a level that remained relatively stable throughout the decade of the 1990s. Errors on the new determination are comparatively large due to the low particle fluxes at solar maximum. Nevertheless, the magnitude of the effect is consistent with predictions based on the assumption that cosmic-ray modulation effects with 22 yr periodicity are related simply and directly to charge sign and large-scale structure of the magnetic field embedded in the solar wind.

Clem, John M.; Evenson, Paul A.

2002-03-01

182

Cosmic rays from the galactic center  

NASA Astrophysics Data System (ADS)

We examine the possibility that recent data on cosmic ray anisotropies presented by the AGASA group may lead to the conclusion that our Galactic Center is a major source of the highest energy cosmic rays in our galaxy. We discuss how such a source would contribute to the magnitude and directional properties of the observed flux when measured against a background of extragalactic cosmic rays. We do this using the results of previous propagation calculations and our own more recent calculations which are specifically for a Galactic Center source. We find that the AGASA data can indeed be plausibly interpreted in this way and also that an argument can be made that the Galactic Center has the appropriate physical properties for acceleration to energies of the order of 10 18 eV. We show that data from the SUGAR array are compatible with the AGASA result.

Clay, R. W.; Dawson, B. R.; Bowen, J.; Debes, M.

2000-01-01

183

Ion acceleration to cosmic ray energies  

NASA Technical Reports Server (NTRS)

The acceleration and transport environment of the outer heliosphere is described schematically. Acceleration occurs where the divergence of the solar-wind flow is negative, that is at shocks, and where second-order Fermi acceleration is possible in the solar-wind turbulence. Acceleration at the solar-wind termination shock is presented by reviewing the spherically-symmetric calculation of Webb et al. (1985). Reacceleration of galactic cosmic rays at the termination shock is not expected to be important in modifying the cosmic ray spectrum, but acceleration of ions injected at the shock up to energies not greater than 300 MeV/charge is expected to occur and to create the anomalous cosmic ray component. Acceleration of energetic particles by solar wind turbulence is expected to play almost no role in the outer heliosphere. The one exception is the energization of interstellar pickup ions beyond the threshold for acceleration at the quasi-perpendicular termination shock.

Lee, Martin A.

1990-01-01

184

Anomalous isotopic composition of cosmic rays  

SciTech Connect

Recent measurements of nonsolar isotopic patterns for the elements neon and (perhaps) magnesium in cosmic rays are interpreted within current models of stellar nucleosynthesis. One possible explanation is that the stars currently responsible for cosmic-ray synthesis in the Galaxy are typically super-metal-rich by a factor of two to three. Other possibilities include the selective acceleration of certain zones or masses of supernovas or the enhancement of /sup 22/Ne in the interstellar medium by mass loss from red giant stars and planetary nebulas. Measurements of critical isotopic ratios are suggested to aid in distinguishing among the various possibilities. Some of these explanations place significant constraints on the fraction of cosmic ray nuclei that must be fresh supernova debris and the masses of the supernovas involved. 1 figure, 3 tables.

Woosley, S.E.; Weaver, T.A.

1980-06-20

185

Cosmic-ray streaming and anisotropies  

NASA Technical Reports Server (NTRS)

The paper is concerned with the differential current densities and anisotropies that exist in the interplanetary cosmic-ray gas, and in particular with a correct formulation and simple interpretation of the momentum equation that describes these on a local basis. Two examples of the use of this equation in the interpretation of previous data are given. It is demonstrated that in interplanetary space, the electric-field drifts and convective flow parallel to the magnetic field of cosmic-ray particles combine as a simple convective flow with the solar wind, and that there exist diffusive currents and transverse gradient drift currents. Thus direct reference to the interplanetary electric-field drifts is eliminated, and the study of steady-state and transient cosmic-ray anisotropies is both more systematic and simpler.

Forman, M. A.; Gleeson, L. J.

1975-01-01

186

The HEAO-3 Cosmic Ray Isotope spectrometer  

NASA Technical Reports Server (NTRS)

This paper describes the Cosmic Ray Isotope instrument launched aboard the HEAO-3 satellite on September 20, 1979. The primary purpose of the experiment is to measure the isotopic composition of cosmic ray nuclei from Be-7 to Fe-58 over the energy range 0.5 to 7 GeV/nucleon. In addition charge spectra will be measured between beryllium and tin over the energy range 0.5 to 25 GeV/nucleon. The charge and isotope abundances measured by the experiment provide essential information needed to further our understanding of the origin and propagation of high energy cosmic rays. The instrument consists of 5 Cerenkov counters, a 4 element neon flash tube hodoscope and a time-of-flight system. The determination of charge and energy for each particle is based on the multiple Cerenkov technique and the mass determination will be based upon a statistical analysis of particle trajectories in the geomagnetic field.

Bouffard, M.; Engelmann, J. J.; Koch, L.; Soutoul, A.; Lund, N.; Peters, B.; Rasmussen, I. L.

1982-01-01

187

Does electromagnetic radiation accelerate galactic cosmic rays  

NASA Technical Reports Server (NTRS)

The 'reactor' theories of Tsytovich and collaborators (1973) of cosmic-ray acceleration by electromagnetic radiation are examined in the context of galactic cosmic rays. It is shown that any isotropic synchrotron or Compton reactors with reasonable astrophysical parameters can yield particles with a maximum relativistic factor of only about 10,000. If they are to produce particles with higher relativistic factors, the losses due to inverse Compton scattering of the electromagnetic radiation in them outweigh the acceleration, and this violates the assumptions of the theory. This is a critical restriction in the context of galactic cosmic rays, which have a power-law spectrum extending up to a relativistic factor of 1 million.

Eichler, D.

1977-01-01

188

Gamma ray bursts and extreme energy cosmic rays  

NASA Astrophysics Data System (ADS)

Extreme Energy Cosmic Ray particles (EECR) with E>1020 eV arriving on Earth with very low flux (~1 particle/Km2-1000yr) require for their investigation very large detecting areas, exceeding values of 1000 km2 sr. Projects with these dimensions are now being proposed: Ground Arrays (``Auger'' with 2×3500 km2 sr) or exploiting the Earth Atmosphere as seen from space (``AIR WATCH'' and OWL,'' with effective area reaching 1 million km2 sr). In this last case, by using as a target the 1013 tons of air viewed, also the high energy neutrino flux can be investigated conveniently. Gamma Rays Bursts are suggested as a possible source for EECR and the associated High Energy neutrino flux.

Scarsi, Livio

1998-06-01

189

Structure Formation Cosmic Rays: Identifying Observational Constraints  

NASA Astrophysics Data System (ADS)

Shocks that arise from baryonic in-fall and merger events during the structure formation are believed to be a source of cosmic rays. These "structure formation cosmic rays" (SFCRs) would essentially be primordial in composition, namely, mostly made of protons and alpha particles. However, very little is known about this population of cosmic rays. One way to test the level of its presence is to look at the products of hadronic reactions between SFCRs and the ISM. A perfect probe of these reactions would be 6Li. The rare isotope 6Li is produced only by cosmic rays, dominantly in alpha alpha rightarrow 6Li fusion reactions with the ISM helium. Consequently, this nuclide provides a unique diagnostic of the history of cosmic rays. Exactly because of this unique property is 6Li affected most by the presence of an additional cosmic ray population. In turn, this could have profound consequences for the Big-Bang nucleosynthesis: cosmic rays created during cosmic structure formation would lead to pre-Galactic Li production, which would act as a "contaminant" to the primordial 7Li content of metal-poor halo stars. Given the already existing problem of establishing the concordance between 7Li observed in halo stars and primordial 7Li as predicted by the WMAP, it is crucial to set limits to the level of this "contamination". However, the history of SFCRs is not very well known. Thus we propose a few model- independent ways of testing the SFCR species and their history, as well as the existing lithium problem: 1) we establish the connection between gamma-ray and 6Li production, which enables us to place constraints on the SFCR-made lithium by using the observed Extragalactic Gamma-Ray Background (EGRB); 2) we propose a new site for testing the primordial and SFCR-made lithium, namely, low-metalicity High-Velocity Clouds (HVCs), which retain the pre-Galactic composition without any significant depletion. Although using one method alone may not give us strong constraints, using them in concert will shed a new light on the SFCR population and possibly give some answers about the pressing lithium problem.

Prodanovic, T.; Fields, B. D.

2005-06-01

190

The origin of galactic cosmic rays  

NASA Astrophysics Data System (ADS)

One century ago Viktor Hess carried out several balloon flights that led him to conclude that the penetrating radiation responsible for the discharge of electroscopes was of extraterrestrial origin. One century from the discovery of this phenomenon seems to be a good time to stop and think about what we have understood about Cosmic Rays. The aim of this review is to illustrate the ideas that have been and are being explored in order to account for the observable quantities related to cosmic rays and to summarize the numerous new pieces of observation that are becoming available. In fact, despite the possible impression that development in this field is somewhat slow, the rate of new discoveries in the last decade or so has been impressive, and mainly driven by beautiful pieces of observation. At the same time scientists in this field have been able to propose new, fascinating ways to investigate particle acceleration inside the sources, making use of multifrequency observations that range from the radio, to the optical, to X-rays and gamma rays. These ideas can now be confronted with data. I will mostly focus on supernova remnants as the most plausible sources of Galactic cosmic rays, and I will review the main aspects of the modern theory of diffusive particle acceleration at supernova remnant shocks, with special attention for the dynamical reaction of accelerated particles on the shock and the phenomenon of magnetic field amplification at the shock. Cosmic-ray escape from the sources is discussed as a necessary step to determine the spectrum of cosmic rays at the Earth. The discussion of these theoretical ideas will always proceed parallel to an account of the data being collected especially in X-ray and gamma-ray astronomy. In the end of this review I will also discuss the phenomenon of cosmic-ray acceleration at shocks propagating in partially ionized media and the implications of this phenomenon in terms of width of the Balmer line emission. This field of research has recently experienced a remarkable growth, in that H? lines have been found to bear information on the cosmic-ray acceleration efficiency of supernova shocks.

Blasi, Pasquale

2013-11-01

191

Cosmic-ray Muon Flux In Belgrade  

SciTech Connect

Two identical plastic scintillator detectors, of prismatic shape (50x23x5)cm similar to NE102, were used for continuous monitoring of cosmic-ray intensity. Muon {delta}E spectra have been taken at five minute intervals, simultaneously from the detector situated on the ground level and from the second one at the depth of 25 m.w.e in the low-level underground laboratory. Sum of all the spectra for the years 2002-2004 has been used to determine the cosmic-ray muon flux at the ground level and in the underground laboratory.

Banjanac, R.; Dragic, A.; Jokovic, D.; Udovicic, V. [Institute of Physics, University of Belgrade, Belgrade (Serbia and Montenegro); Puzovic, J.; Anicin, I. [Faculty of Physics, University of Belgrade, Belgrade (Serbia and Montenegro)

2007-04-23

192

Precursor shocks and cosmic ray acceleration  

NASA Astrophysics Data System (ADS)

Cosmic ray acceleration takes place in shocks of relativistic jets in Active Galactic Nuclei (AGN). The diffusive or stochastic acceleration are believed to be the main responsible mechanisms. Additionally, it is known that the back-reaction of accelerated cosmic rays in shock fronts in astrophysical environments, may lead to the formation of a precursor shock with a length scale which corresponds to the diffusive scale of the energetic particles. In this work we will investigate the properties of relativistic, parallel and perpendicular precursor shocks, via numerical test-particle simulations, allowing diffusive and stochastic acceleration.

Meli, A.

2013-02-01

193

Isotopic composition of heavy cosmic rays  

NASA Technical Reports Server (NTRS)

The mean isotopic composition was measured of even-charge cosmic ray elements with 14 equal to or less than 26 near 0.8 GeV/N using a balloon-borne ionization-chamber/Cerenkov-counter detector system. The experimental method makes use of the geomagnetic field as a magnetic spectrometer. Results indicate that the most abundant isotopes at the cosmic ray source are Si-28, S-32, and Ca-40, like the solar system; but Fe-54, unlike the solar system.

Maehl, R. C.; Isreal, M. H.; Klarmann, J.

1973-01-01

194

A Tale of Cosmic Rays Narrated in ? Rays by Fermi  

NASA Astrophysics Data System (ADS)

Because cosmic rays are charged particles scrambled by magnetic fields, combining direct measurements with other observations is crucial to understanding their origin and propagation. As energetic particles traverse matter and electromagnetic fields, they leave marks in the form of neutral interaction products. Among those, ? rays trace interactions of nuclei that inelastically collide with interstellar gas, as well as of leptons that undergo Bremsstrahlung and inverse-Compton scattering. Data collected by the Fermi large area telescope (LAT) are therefore telling us the story of cosmic rays along their journey from sources through their home galaxies. Supernova remnants emerge as a notable ?-ray source population, and older remnants interacting with interstellar matter finally show strong evidence of the presence of accelerated nuclei. Yet the maximum energy attained by shock accelerators is poorly constrained by observations. Cygnus X, a massive star-forming region established by the LAT as housing cosmic-ray sources, provides a test case to study the impact of wind-driven turbulence on the early propagation. Interstellar emission resulting from the large-scale propagation of cosmic rays in the Milky Way is revealed in unprecedented detail that challenges some of the simple assumptions used for the modeling. Moreover, the cosmic-ray induced ?-ray luminosities of galaxies-scale quasi-linearly with their massive-star formation rates: the overall normalization of that relation below the calorimetric limit suggests that for most systems, a substantial fraction of energy in cosmic rays escapes into the intergalactic medium. The nuclear production models and the distribution of target gas and radiation fields, not determined precisely enough yet, are key to exploiting the full potential of ?-ray data. Nevertheless, data being collected by Fermi and complementary multiwavelength/multimessenger observations are bringing us ever closer to solving the cosmic-ray mystery.

Tibaldo, Luigi

2014-05-01

195

Ground level observations of cosmic rays with neutron monitors  

NASA Astrophysics Data System (ADS)

Cosmic rays are high-energy atomic nuclei, produced mainly in the galaxy. They propagate through the heliosphere, penetrate the geomagnetic field and interact with the atmospheric nuclei to form a cascade of secondary particles. Cosmic rays can be detected by spacecraft and recorded by detectors on the earth, e.g. neutron monitors. Space experiments have the advantages above neutron monitor measurements that the primary cosmic rays are detected directly, and that their detectors measure intensities in pre-determined energy levels, from which energy spectra can be obtained. However, neutron monitors are complementary to spacecraft measurements by detecting particles in a long-term and continuous way, as well as with energies about a decade higher than possible with most spacecraft. Calibration neutron monitors were built for normalizing neutron monitors worldwide in order to obtain energy spectra. Properties of the calibrators were investigated, and at present we have started to calibrate the stationary neutron monitors. This presentation reviews the relation between ground and space based detectors of cosmic rays with emphasis on the mentioned calibration process of neutron monitors.

Kruger, Helena; Moraal, Harm

196

Research in cosmic and gamma ray astrophysics: Cosmic physics portion  

NASA Technical Reports Server (NTRS)

Research in particle astrophysics at the Space Radiation Laboratory (SRL) of the California Institute of Technology is supported under NASA Grant NAGW-1919. A three-year proposal for continuation of support was submitted a year ago and put into effect 1 October 1992. This report is the combined progress report and continuation application called for under the Federal Demonstration Project. Gamma-ray Astrophysics at SRL is separately supported under NAGW-1919 and will be separately summarized and proposed. This report will document progress and plans for our particle spectroscopy activities and for related data analysis, calibration, and community service activities. A bibliography and a budget will be attached as appendices. The Caltech SRL research program includes a heavy emphasis on elemental and isotopic spectroscopy of energetic particles in the cosmic radiation; in solar, interplanetary, and anomalous 'cosmic' radiation; and in planetary magnetospheres as discussed.

Stone, Edward C.; Mewaldt, Richard A.; Schindler, Stephen

1993-01-01

197

Cosmic-ray positrons from mature gamma-ray pulsars  

Microsoft Academic Search

We consider a possible contribution of mature gamma -ray pulsars (with ages of >= 105 yrs) to cosmic ray positrons. Within the framework of the gamma -ray pulsar outer gap model, e+\\/- pairs in the pulsar magnetosphere are produced by the cascade of e+\\/- pairs through synchrotron radiation of the return current from the outer gap. A good fraction of

L. Zhang; K. S. Cheng

2001-01-01

198

Pulsars, supernovae, and ultrahigh energy cosmic rays  

NASA Astrophysics Data System (ADS)

The acceleration of ultrahigh energy nuclei in fast spinning newborn pulsars can explain the observed spectrum of ultrahigh energy cosmic rays and the trend towards heavier nuclei for energies above 10^{19} eV as indicated by air shower studies reported by the Auger Observatory. By assuming a normal distribution of pulsar birth periods centered at 300 ms, we show that the contribution of extragalactic pulsar births to the ultrahigh energy cosmic ray spectrum naturally gives rise to a contribution to very high energy cosmic rays (VHECRs, between 10^{16} and 10^{18} eV) by Galactic pulsar births. The required injected composition to fit the observed spectrum depends on the absolute energy scale, differing considerably between the energy scale used by Auger and that used by the Telescope Array. Depending on the composition of the cosmic rays that escape the supernova remnant and the diffusion behavior of VHECRs in the Galaxy, the contribution of Galactic pulsar births can also bridge the gap between predictions for cosmic ray acceleration in supernova remnants and the observed spectrum below the ankle. Fast spinning newborn pulsars that could produce UHECRs would be born in supernovae that could present interesting specific radiative features, due to the interaction of the pulsar wind with the surrounding ejecta. The resulting supernova lightcurves could present a high luminosity plateau over a few years, and a bright X-ray and gamma-ray peak around one or two years after the onset of the explosion. If such signatures were observed, they could have important implications both for UHECR astrophysics and for the understanding of core-collapse supernovae.

Kotera, K.; Fang, K.; Olinto, A. V.; Phinney, E. S.

2012-12-01

199

Relic neutrino masses and the highest energy cosmic rays  

NASA Astrophysics Data System (ADS)

We consider the possibility that a large fraction of the ultrahigh energy cosmic rays are decay products of Z bosons which were produced in the scattering of ultrahigh energy cosmic neutrinos on cosmological relic neutrinos. We compare the observed ultrahigh energy cosmic ray spectrum with the one predicted in the above Z-burst scenario and determine the required mass of the heaviest relic neutrino as well as the necessary ultrahigh energy cosmic neutrino flux via a maximum likelihood analysis. We show that the value of the neutrino mass obtained in this way is fairly robust against variations in presently unknown quantities, like the amount of neutrino clustering, the universal radio background, and the extragalactic magnetic field, within their anticipated uncertainties. Much stronger systematics arises from different possible assumptions about the diffuse background of ordinary cosmic rays from unresolved astrophysical sources. In the most plausible case that these ordinary cosmic rays are protons of extragalactic origin, one is lead to a required neutrino mass in the range 0.08 eV leq mnu leq 1.3 eV at the 68 % confidence level. This range narrows down considerably if a particular universal radio background is assumed, e.g. to 0.08 eV leq mnu leq 0.40 eV for a large one. The required flux of ultrahigh energy cosmic neutrinos near the resonant energy should be detected in the near future by AMANDA, RICE, and the Pierre Auger Observatory, otherwise the Z-burst scenario will be ruled out.

Fodor, Zoltan; Katz, Sandor D.; Ringwald, Andreas

2002-06-01

200

Cosmic Ray Transport in the Distant Heliosheath  

NASA Technical Reports Server (NTRS)

The character of energetic particle transport in the distant heliosheath and especially in the vicinity of the heliopause could be quite distinct from the other regions of the heliosphere. The magnetic field structure is dominated by a tightly wrapped oscillating heliospheric current sheet which is transported to higher latitudes by the nonradial heliosheath flows. Both Voyagers have, or are expected to enter a region dominated by the sectored field formed during the preceding solar maximum. As the plasma flow slows down on approach to the heliopause, the distance between the folds of the current sheet decreases to the point where it becomes comparable to the cyclotron radius of an energetic ion, such as a galactic cosmic ray. Then, a charged particle can effectively drift across a stack of magnetic sectors with a speed comparable with the particle s velocity. Cosmic rays should also be able to efficiently diffuse across the mean magnetic field if the distance between sector boundaries varies. The region of the heliopause could thus be much more permeable to cosmic rays than was previously thought. This new transport proposed mechanism could explain the very high intensities (approaching the model interstellar values) of galactic cosmic rays measured by Voyager 1 during 2010-2011.

Florinski, V.; Adams, James H.; Washimi, H.

2011-01-01

201

Numerical likelihood analysis of cosmic ray anisotropies  

SciTech Connect

A numerical likelihood approach to the determination of cosmic ray anisotropies is presented which offers many advantages over other approaches. It allows a wide range of statistically meaningful hypotheses to be compared even when full sky coverage is unavailable, can be readily extended in order to include measurement errors, and makes maximum unbiased use of all available information.

Carlos Hojvat et al.

2003-07-02

202

Statistical Reconstruction for Cosmic Ray Muon Tomography  

Microsoft Academic Search

Highly penetrating cosmic ray muons constantly shower the earth at a rate of about 1 muon per cm2 per minute. We have developed a technique which exploits the multiple Coulomb scattering of these particles to perform nondestructive inspection without the use of artificial radiation. In prior work , we have described heuristic methods for processing muon data to create reconstructed

Larry Joe Schultz; Gary Stephen Blanpied; Konstantin N. Borozdin; Andrew M. Fraser; Nicholas W. Hengartner; Alexei V. Klimenko; Christopher L. Morris; Chris Orum; Michael J. Sossong

2007-01-01

203

Isotopic Composition of Heavy Cosmic Rays.  

National Technical Information Service (NTIS)

The mean isotopic composition was measured of even-charge cosmic ray elements with 14 equal to or less than 26 near 0.8 GeV/N using a balloon-borne ionization-chamber/Cerenkov-counter detector system. The experimental method makes use of the geomagnetic f...

J. Klarmann M. H. Isreal R. C. Maehl

1973-01-01

204

Cosmic Rays Astrophysics: The Discipline, Its Scope, and Its Applications  

NASA Technical Reports Server (NTRS)

This slide presentation gives an overview of the discipline surrounding cosmic ray astrophysics. It includes information on recent assertions surrounding cosmic rays, exposure levels, and a short history with specific information on the origin, acceleration, transport, and modulation of cosmic rays.

Barghouty, A. F.

2009-01-01

205

Swiss neutron monitors and cosmic ray research at Jungfraujoch  

NASA Astrophysics Data System (ADS)

This review summarizes the history of cosmic ray research at Jungfraujoch, the installation of three neutron monitors in Switzerland, and highlights a few of the main results by the Cosmic Ray Group of the Physikalisches Institut, Universität Bern, Switzerland. In addition, the outstanding scientific and personal contribution of the late Hermann Debrunner, the longtime leader of the Bern Cosmic Ray Group, is honored.

Flückiger, Erwin O.; Bütikofer, Rolf

2009-11-01

206

Cosmic rays from primordial black holes  

NASA Technical Reports Server (NTRS)

The quark and gluon emission from primordial black holes (PBHs) which may have formed from initial density perturbations or phase transitions in the early universe are investigated. If the PBHs formed from scale-invariant initial density perturbations in the radiation dominated era, it is found that the emission can explain or contribute significantly to the extragalactic photon and interstellar cosmic-ray electron, positron, and antiproton spectra around 0.1-1 GeV. In particular, the PBH emission strongly resembles the cosmic-ray gamma-ray spectrum between 50 and 170 MeV. The upper limits on the PBH density today from the gamma-ray, e(+), e(-), and antiproton data are comparable, provided that the PBHs cluster to the same degree as the other matter in the Galactic halo.

Macgibbon, Jane H.; Carr, B. J.

1991-01-01

207

Propagation of Cosmic Rays and Diffuse Galactic Gamma Rays  

NASA Technical Reports Server (NTRS)

This paper presents an introduction to the astrophysics of cosmic rays and diffuse gamma-rays and discusses some of the puzzles that have emerged recently due to more precise data and improved propagation models: the excesses in Galactic diffuse gamma-ray emission, secondary antiprotons and positrons, and the flatter than expected gradient of cosmic rays in the Galaxy. These also involve the dark matter, a challenge to modern physics, through its indirect searches in cosmic rays. Though the final solutions are yet to be found, I discuss some ideas and results obtained mostly with the numerical propagation model GALPROP. A fleet of spacecraft and balloon experiments targeting these specific issues is set to lift off in a few years, imparting a feeling of optimism that a new era of exciting discoveries is just around the corner. A complete and comprehensive discussion of all the recent results is not attempted here due to the space limitations.

Moskalenko, Igor V.

2004-01-01

208

Cosmic Rays for Heliospheric Space Weather Storm Prediction  

NASA Astrophysics Data System (ADS)

The classical imaging of CME's by solar UV light is successfully applied on many satellites like for instance on SOHO, STEREO A and B or SDO. CME detection via UV light from ground based telescopes can't be carried out, because of the absorption of UV light in the Earth atmosphere. However CME detection is done on ground by means of cosmic ray muon telescopes in the Global Muon Detection Network (GMDN). Therefore the astrophysics and solar physics for GMDN are summarized in chapter 1. GMDN data and results are described in chapter 2. A space situational awareness (SSA) satellite, which has also the purpose of CME imaging by means of a telescope for cosmic rays are sketched in chapter 3.

Jansen, Frank; Behrens, Jörg

2011-06-01

209

Measurement of Cosmic-Ray TeV Electrons  

NASA Astrophysics Data System (ADS)

The Cosmic Ray Electron Synchrotron Telescope (CREST) high-altitude balloon experiment is a pathfinding effort to detect for the first time multi-TeV cosmic-ray electrons. At these energies distant sources will not contribute to the local electron spectrum due to the strong energy losses of the electrons and thus TeV observations will reflect the distribution and abundance of nearby acceleration sites. CREST will detect electrons indirectly by measuring the characteristic synchrotron photons generated in the Earth's magnetic field. The instrument consist of an array of 1024 BaF2 crystals viewed by photomultiplier tubes surrounded by a hermetic scintillator shield. Since the primary electron itself need not traverse the payload, an effective detection area is achieved that is several times the nominal 6.4 m2 instrument. CREST is scheduled to fly in a long duration circumpolar orbit over Antarctica during the 2011-12 season.

Schubnell, Michael; Anderson, T.; Bower, C.; Coutu, S.; Gennaro, J.; Geske, M.; Mueller, D.; Musser, J.; Nutter, S.; Park, N.; Tarle, G.; Wakely, S.

2011-09-01

210

Life extinctions by cosmic ray jets.  

NASA Astrophysics Data System (ADS)

High energy cosmic ray jets from nearby mergers or accretion induced collapse (AIC) of neutron stars (NS) that hit the atmosphere can produce lethal fluxes of atmospheric muons at ground level, underground and underwater, destroy the ozone layer and radioactivate the environment. They could have caused most of the massive life extinctions on planet Earth in the past 600 My. Biological mutations due to ionizing radiations could have caused the fast appearance of new species after the massive extinctions. An early warning of future extinctions due to NS mergers may be obtained by identifying, mapping and timing all the nearby binary neutron stars systems. A warning of an approaching cosmic ray burst from a nearby NS merger/AIC may be provided by a very intense gamma ray burst which precedes it.

Dar, A.

211

Cosmic-Ray Transport and Interaction with Shocks  

NASA Astrophysics Data System (ADS)

This paper reviews selected topics in cosmic-ray transport in the heliosphere, as well as recent insights on the interaction of cosmic rays with shocks. Topics include: (a) recent observations suggesting very long inferred scattering mean-free paths of cosmic rays, (b) recent insights into the diffusion of cosmic rays normal to a magnetic field, (c) the physics of super-diffusion and sub-diffusion, and (e) the interaction of cosmic rays with shocks moving through large-scale irregular magnetic fields.

Giacalone, Joe

2013-06-01

212

Active Galactic Nuclei:. Sources for Ultra High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

Ultra high energy cosmic ray events presently show a spectrum, which we interpret here as galactic cosmic rays due to a starburst, in the radio galaxy Cen A which is pushed up in energy by the shock of a relativistic jet. The knee feature and the particles with energy immediately higher in galactic cosmic rays then turn into the bulk of ultra high energy cosmic rays. This entails that all ultra high energy cosmic rays are heavy nuclei. This picture is viable if the majority of the observed ultra high energy events come from the radio galaxy Cen A, and are scattered by intergalactic magnetic fields across much of the sky.

Biermann, P. L.; Becker, J. K.; Caramete, L.; Gergely, L.; Mari?, I. C.; Meli, A.; de Souza, V.; Stanev, T.

213

Gamma Rays, Cosmic Rays and the Dynamics of the Galaxy.  

National Technical Information Service (NTIS)

The galactic gamma ray emission has recently been observed by the SAS-2 and COS-B satellites; the impact of these results on our knowledge of galactic cosmic rays and the interstellar medium is summarized. Despite the fact that an unknown proportion of th...

C. Cesarsky

1978-01-01

214

Future Cosmic-ray Observations On Balloons - Challenges And Requirements  

NASA Astrophysics Data System (ADS)

A number of advanced technologies have now reached maturity for applications in cosmic-ray research on long-duration balloon flights. Examples of these include superconducting magnet technology, precise particle tracking devices, transition radiation detectors, and a variety of advanced Cherenkov counters, combined with high-speed and high-volume data readout, processing and storage systems. If these technologies are incorporated into large-area detector systems, definitive answers to long-standing questions of astrophysical and cosmological importance can be expected. We will discuss several examples: the precise measurement of cosmic-ray positrons and its potential for dark-matter searches; studies of the Galactic propagation of cosmic rays through precise observations of secondary nuclei at the highest energies; and studies of the acceleration process through the detection of the individual energy spectra of cosmic-ray nuclei at the highest energies. While initial measurements on some of these topics have been made in pioneering observations in the past, we will emphasize the potential for great advances that lie ahead if the most modern technologies are coupled with the potential of the long-duration balloon vehicle.

Wakely, Scott; Boyle, P.; Muller, D.; Swordy, S.

2009-01-01

215

Cosmic-ray Exposure Ages of Meteorites  

NASA Astrophysics Data System (ADS)

The classic idea of a cosmic-ray exposure (CRE) age for a meteorite is based on a simple but useful picture of meteorite evolution, the one-stage irradiation model. The precursor rock starts out on a parent body, buried under a mantle of material many meters thick that screens out cosmic rays. At a time ti, a collision excavates a precursor rock - a "meteoroid." The newly liberated meteoroid, now fully exposed to cosmic rays, orbits the Sun until a time tf, when it strikes the Earth, where the overlying blanket of air (and possibly of water or ice) again shuts out almost all cosmic rays (cf. Masarik and Reedy, 1995). The quantity tf-ti is called the CRE age, t. To obtain the CRE age of a meteorite, we measure the concentrations in it of one or more cosmogenic nuclides (Table 1), which are nuclides that cosmic rays produce by inducing nuclear reactions. Many shorter-lived radionuclides excluded from Table 1 such as 22Na (t1/2=2.6 yr) and 60Co (t1/2=5.27 yr) can also furnish valuable information, but can be measured only in meteorites that fell within the last few half-lives of those nuclides (see, e.g., Leya et al. (2001) and references therein). Table 1. Cosmogenic nuclides used for calculating exposure ages NuclideHalf-lifea (Myr) Radionuclides 14C0.005730 59Ni0.076 41Ca0.1034 81Kr0.229 36Cl0.301 26Al0.717 10Be1.51 53Mn3.74 129I15.7 Stable nuclides 3He 21Ne 38Ar 83Kr 126Xe a http://www2.bnl.gov/ton. CRE ages have implications for several interrelated questions. From how many different parent bodies do meteorites come? How well do meteorites represent the population of the asteroid belt? How many distinct collisions on each parent body have created the known meteorites of each type? How often do asteroids collide? How big and how energetic were the collisions that produced meteoroids? What factors control the CRE age of a meteorite and how do meteoroid orbits evolve through time? We will touch on these questions below as we examine the data.By 1975, the CRE ages of hundreds of meteorites had been estimated from noble gas measurements. Histograms of the CRE age distributions pointed to several important observations.(i) The CRE ages of meteorites increase in the order stones detection limits for cosmogenic nuclides and

Herzog, G. F.

2003-12-01

216

Nuclear composition of solar cosmic rays  

NASA Technical Reports Server (NTRS)

Experimental observations of the elemental and isotopic composition of solar flare particles are discussed. Sources and characteristics of particle-emitting solar flare events are reviewed, and techniques for separating particle species are briefly described. Data are presented for the elemental composition of the solar atmosphere, and the possibility of determining the solar helium abundance from solar cosmic-ray observations is explored. The main experimental determinations of heavy element abundances at energies greater and less than 10 MeV/nucleon are summarized, and techniques for measuring the ionic charge composition of solar cosmic rays are outlined. Models explaining heavy element enhancements are described along with processes leading to gamma-ray emission during solar flare events. Observations of the rare isotopes of hydrogen and helium during solar flare events are noted, and a lower atmospheric limit is derived for nuclear reactions leading to positron decay. The possibility of investigating low-energy solar cosmic rays by measuring the relative abundances of different elements is evaluated.

Hovestadt, D.

1974-01-01

217

Terrestrial effects of high energy cosmic rays  

NASA Astrophysics Data System (ADS)

On geological timescales, the Earth is likely to be exposed to higher than the usual flux of high energy cosmic rays (HECRs) from astrophysical sources such as nearby supernovae, gamma ray bursts or by galactic shocks. These high-energy particles strike the Earth's atmosphere, initiating an extensive air shower. As the air shower propagates deeper, it ionizes the atmosphere by producing charged secondary particles and photons. Increased ionization leads to changes in atmospheric chemistry, resulting in ozone depletion. This increases the flux of solar UVB radiation at the surface, which is potentially harmful to living organisms. Increased ionization affects the global electrical circuit, which could enhance the low-altitude cloud formation rate. Secondary particles such as muons and thermal neutrons produced as a result of hadronic interactions of the primary cosmic rays with the atmosphere are able to reach the ground, enhancing the biological radiation dose. The muon flux dominates the radiation dose from cosmic rays causing damage to DNA and an increase in mutation rates and cancer, which can have serious biological implications for surface and sub-surface life. Using CORSIKA, we perform massive computer simulations and construct lookup tables for 10 GeV - 1 PeV primaries, which can be used to quantify these effects from enhanced cosmic ray exposure to any astrophysical source. These tables are freely available to the community and can be used for other studies. We use these tables to study the terrestrial implications of galactic shock generated by the infall of our galaxy toward the Virgo cluster. Increased radiation dose from muons could be a possible mechanism explaining the observed periodicity in biodiversity in paleobiology databases.

Atri, Dimitra

218

Ultrahigh Energy Cosmic Rays: Old Physics or New Physics?  

NASA Astrophysics Data System (ADS)

We consider the advantages of and the problems associated with hypotheses to explain the origin of ultrahigh energy cosmic rays (UHECR: E > 10 EeV) and the “trans-GZK” cosmic rays (TGZK: E > 100 EeV) both through “old physics” (acceleration in cosmic sources) and “new physics” (new particles, topological defects, fat neutrino cross sections, Lorentz invariance violation).

Stecker, F. W.

2004-11-01

219

Cosmic X-ray physics  

NASA Technical Reports Server (NTRS)

The analysis of the beryllium-filtered data from Flight 17.020 was completed. The data base provided by the Wisconsin diffuse X-ray sky survey is being analyzed by correlating the B and C band emission with individual velocity components of neutral hydrogen. Work on a solid state detector to be used in high resolution spectroscopy of diffuse or extend X-ray sources is continuing. A series of 21 cm observations was completed. A paper on the effects of process parameter variation on the reflectivity of sputter-deposited tungsten-carvon multilayers was published.

Mccammon, D.; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1986-01-01

220

TRACING THE SOURCES OF COSMIC RAYS WITH MOLECULAR IONS  

SciTech Connect

The rate of ionization by cosmic rays (CRs) in interstellar gas directly associated with {gamma}-ray-emitting supernova remnants (SNRs) is for the first time calculated to be several orders of magnitude larger than the Galactic average. Analysis of ionization-induced chemistry yields the first quantitative prediction of the astrophysical H{sup +} {sub 2} emission line spectrum, which should be detectable together with H{sup +} {sub 3} lines. The predicted coincident observation of those emission lines and {gamma}-rays will help prove that SNRs are sources of CRs.

Becker, Julia K.; Schuppan, Florian [Ruhr-Universitaet Bochum, Fakultaet fuer Physik and Astronomie, Theoretische Physik IV, D-44780 Bochum (Germany); Black, John H.; Mohammadtaher Safarzadeh, E-mail: julia@tp4.rub.de [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala (Sweden)

2011-10-01

221

Neutrinos associated with cosmic rays of top-down origin  

NASA Astrophysics Data System (ADS)

Top-down models of cosmic rays produce more neutrinos than photons and more photons than protons. In these models, we reevaluate the fluxes of neutrinos associated with the highest energy cosmic rays in light of mounting evidence that they are protons and not gamma rays. While proton dominance at EeV energies can possibly be achieved by efficient absorption of the dominant high-energy photon flux on universal and galactic photon and magnetic background fields, we show that the associated neutrino flux is inevitably increased to a level where it might be within reach of operating experiments such as AMANDA II, RICE and AGASA. In future neutrino telescopes, tens to a hundred, rather than a few neutrinos per kilometer squared per year, may be detected above 100 TeV.

Barbot, C.; Drees, M.; Halzen, F.; Hooper, D.

2003-02-01

222

Measuring cosmic ray radio signals at the Pierre Auger Observatory  

NASA Astrophysics Data System (ADS)

The recent results of the LOPES and CODALEMA experiments open the door to a renewal of the radio technique for cosmic ray induced shower measurements. The demonstration has been done of its potential and performances at energies below 1018 eV, this upper limit being due to the small scale of the current experiments. A natural stage toward the improvement of the method is thus to install radio detectors in association with a large cosmic ray detector such as Auger. Besides surface and fluorescence detection, radio detection could be an alternative method, providing a complementary information. The Pierre Auger Collaboration has thus engaged a R&D effort which will lead to the installation of a radio engineering array covering 20 km2 on its southern site. Outline of the technique, results of the first phase of the tests and current plans for the future engineering array will be presented.

Dallier, Richard; Pierre Auger Collaboration

2011-02-01

223

Recent cosmic-ray antiproton measurements and astrophysical implications  

NASA Technical Reports Server (NTRS)

Cosmic-ray antiprotons have been detected by a new balloon-borne experiment which covers the energy range between 130 and 320 MeV. Fourteen detected events yield a measured flux of 1.7 plus or minus 0.5 x 10 to the -4th antiprotons/sq m sr s MeV. The corresponding antiproton/proton ratio is 2.2 plus or minus 0.6 x 10 to the -4th, only slightly smaller than the ratio observed by other experiments at higher energies. The measured flux is significantly larger than predicted, and some cosmic-ray models which could explain this result are discussed.

Buffington, A.; Schindler, S. M.

1981-01-01

224

Cosmic X-ray physics  

Microsoft Academic Search

The soft X-ray sky survey data are combined with the results from the UXT sounding rocket payload. Very strong constraints can then be placed on models of the origin of the soft diffuse background. Additional observational constraints force more complicated and realistic models. Significant progress was made in the extraction of more detailed spectral information from the UXT data set.

D. McCammon; D. P. Cox; W. L. Kraushaar; W. T. Sanders

1987-01-01

225

On the interplanetary cosmic ray latitudinal gradient  

NASA Technical Reports Server (NTRS)

Results are presented from measurements, from 1983 to 1990, of the temporal history of the latitudinal and radial gradients of cosmic ray particles with E greater than 70-MeV. The data used include measurements obtained by the Voyager 2 and Pioneer 10 spacecraft near the heliographic equatorial plane, and from Pioneer 11 and Voyager 1 at average latitudes of 16 deg and 30 deg, respectively. Using the data from Pioneer 11 and Voyager 1 at different altitudes, the altitude dependence of the 26-day-average differential cosmic ray latitudinal gradient was deduced. The gradient was found to be a strong function of latitude when the tilt angle approached zero and became essentially independent of latitude for tilt angles above 30 deg. The relationship between the latitudinal and radial gradients was used to estimate the perpendicular diffusion coefficient for E greater than 7-MeV particles.

Lockwood, J. A.; Webber, W. R.

1992-01-01

226

Electron cosmic ray measurements in space  

NASA Astrophysics Data System (ADS)

Measurements of the electron and positron cosmic rays provide important information on the cosmic ray sources and on the mechanisms of their acceleration and propagation in the Galaxy. They are also major candidates for searching signals from annihilation of dark matter and contributions from other exotic sources as nearby pulsars. Many balloon-borne experiments have been performed since the sixties, but only recently by the PAMELA and Fermi satellite experiments have been possible to obtain reliable high statistics results up to 1 TeV that have highlighted interesting structures that have promoted a large number of theoretical ideas. AMS-02 ISS experiment is foreseen to release data on electrons and positrons in the next future.

Picozza, P.; Marcelli, L.

2014-01-01

227

Cosmic ray acceleration at modified shocks  

NASA Astrophysics Data System (ADS)

The non-linear back reaction of accelerated cosmic rays at a non-relativistic shock front leads to the formation of a smooth precursor with a length scale corresponding to the diffusive scale of the energetic particles. The instabilities present in these modified shocks may play a crucial role as past theoretical work has shown. First, it was claimed that shocklets that could be created in the precursor region of a specific width might energize few thermal particles to sufficient acceleration and second, some precursor regions may act as confining large angle scatterers for very high energy cosmic rays. Our aim here is to investigate numerically these claims by constructing a Monte Carlo code simulating the above conditions which could throw further light to the exact mechanism of efficiency, particularly in the case of highly oblique shocks as these appear in nature much more often.

Meli, A.; Biermann, P. L.; Dimitrakoudis, S.

228

Radiative Energy Loss by Galactic Cosmic Rays  

NASA Technical Reports Server (NTRS)

Interactions between galactic cosmic rays and matter are a primary focus of the NASA radiation problem. The electromagnetic forces involved are for the most part well documented. Building on previous research, this study investigated the relative importance of the weak forces that occur when a cosmic ray impinges on different types of materials. For the familiar electromagnetic case, it is known that energy lost in the form of radiation is more significant than that lost via contact collisions the rate at which the energy is lost is also well understood. Similar results were derived for the weak force case. It was found that radiation is also the dominant mode of energy loss in weak force interactions and that weak force effects are indeed relatively weak compared to electromagnetic effects.

Ahern, Sean C.; Norbury, John W.; Tripathi, R. K.

2002-01-01

229

Focusing anisotropy of solar cosmic rays  

NASA Technical Reports Server (NTRS)

Analysis of 50-MeV particle data from ICE and 1-GeV data from eight high-latitude neutron monitors of the February 16, 1984 solar cosmic ray event indicates that an exponential with scattering mean free path of greater than 2 AU and with index in the 1.3-1.7 range provides a better description of particle anisotropies than the first-order form, confirming the prediction from cosmic ray transport theories which incorporate the effect of adiabatic focusing into the usual pitch angle scattering formalism. The time profile of the event is largely a reflection of coronal transport processes, with good fits provided by a coronal diffusion coefficient of about 10 to the 18th sq cm/s and with velocity-dependent escape. The simple method of predicting the interplanetary scattering parameters has application where particle injection is nearly continuous, but where previously accelerated particles have filled the heliosphere with a large omnidirectional background.

Bieber, J. W.; Evenson, P. A.; Pomerantz, M. A.

1986-01-01

230

Strangelet propagation and cosmic ray flux  

SciTech Connect

The galactic propagation of cosmic ray strangelets is described and the resulting flux is calculated for a wide range of parameters as a prerequisite for strangelet searches in lunar soil and with an Earth orbiting magnetic spectrometer, AMS-02. While the inherent uncertainties are large, flux predictions at a measurable level are obtained for reasonable choices of parameters if strange quark matter is absolutely stable. This allows a direct test of the strange matter hypothesis.

Madsen, Jes [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)

2005-01-01

231

Galactic cosmic ray modulation from 1965 1970  

Microsoft Academic Search

Numerical solutions of the cosmic-ray equation of transport within the solar cavity and including the effects of diffusion, convection, and energy losses due to adiabatic deceleration, have been used to reproduce the modulation of galactic electrons, protons and helium nuclei observed during the period 1965 1970. Kinetic energies between 10 and 104 MeV\\/nucleon are considered. Computed and observed spectra (where

I. H. Urch; L. J. Gleeson

1972-01-01

232

Scientific Set of Instruments "Solar Cosmic Rays"  

NASA Astrophysics Data System (ADS)

A set of scientific instruments SCR (Solar Cosmic Rays) was developed by the scientists of SINP MSU and IEP SAS in order to study relations between the radiation conditions in the near-Earth space and solar activity. This set of instruments was installed on board the satellites CORONAS-I and CORONAS-F launched to the orbit on March 2, 1994, and July 30, 2001, respectively. Detailed description of the instruments is presented.

Kuznetsov, S. N.; Bogomolov, A. V.; Galkin, V. I.; Denisov, Yu. I.; Podorolsky, A. N.; Ryumin, S. P.; Kudela, K.; Rojko, J.

233

Anisotropy and Corotation of Galactic Cosmic Rays  

Microsoft Academic Search

The intensity of Galactic cosmic rays is nearly isotropic because of the influence of magnetic fields in the Milky Way. Here, we present two-dimensional high-precision anisotropy measurement for energies from a few to several hundred teraelectronvolts (TeV), using the large data sample of the Tibet Air Shower Arrays. Besides revealing finer details of the known anisotropies, a new component of

M. Amenomori; S. Ayabe; X. J. Bi; D. Chen; S. W. Cui; Danzengluobu; L. K. Ding; X. H. Ding; C. F. Feng; Zhaoyang Feng; Z. Y. Feng; X. Y. Gao; Q. X. Geng; H. W. Guo; H. H. He; M. He; K. Hibino; N. Hotta; Haibing Hu; H. B. Hu; J. Huang; Q. Huang; H. Y. Jia; F. Kajino; K. Kasahara; Y. Katayose; C. Kato; K. Kawata; Labaciren; G. M. Le; A. F. Li; J. Y. Li; Y.-Q. Lou; H. Lu; S. L. Lu; X. R. Meng; K. Mizutani; J. Mu; K. Munakata; A. Nagai; H. Nanjo; M. Nishizawa; M. Ohnishi; I. Ohta; H. Onuma; T. Ouchi; S. Ozawa; J. R. Ren; T. Saito; M. Sakata; T. K. Sako; T. Sasaki; M. Shibata; A. Shiomi; T. Shirai; H. Sugimoto; M. Takita; Y. H. Tan; N. Tateyama; S. Torii; H. Tsuchiya; S. Udo; B. Wang; H. Wang; X. Wang; Y. G. Wang; H. R. Wu; L. Xue; Y. Yamamoto; C. T. Yan; X. C. Yang; S. Yasue; Z. H. Ye; G. C. Yu; A. F. Yuan; T. Yuda; H. M. Zhang; J. L. Zhang; N. J. Zhang; X. Y. Zhang; Y. Zhang; Yi Zhang; Zhaxisangzhu; X. X. Zhou

2006-01-01

234

Cosmic ray decreases: 1964-1994  

Microsoft Academic Search

We have studied 30 years (1964-1994) of neutron monitor data in order to understand the principle mechanisms causing short-term (<20-day duration) cosmic ray decreases seen at Earth. By examining the characteristics of associated low energy (=4% decreases. The vast majority (86% of the 153 events) are caused by coronal mass ejections and the shocks that they generate. The ejecta is

H. V. Cane; I. G. Richardson; T. T. von Rosenvinge

1996-01-01

235

Cosmic ray decreases: 1964–1994  

Microsoft Academic Search

We have studied 30 years (1964-1994) of neutron monitor data in order to understand the principle mechanisms causing short-term (< 20-day duration) cosmic ray decreases seen at Earth. By examining the characteristics of associated low energy (<200 MeV) particle enhancements in combination with the neutron monitor data, we have determined the responsible solar wind disturbances for 153 of the 180

H. V. Cane; I. G. Richardson; T. T. von Rosenvinge

1996-01-01

236

Cosmic ray measurements with Pamela experiment  

Microsoft Academic Search

PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antinuclei with a precision of the order

M. Casolino; N. De Simone; M. P. De Pascale; V. Di Felice; L. Marcelli; M. Minori; P. Picozza; R. Sparvoli; G. Castellini; O. Adriani; L. Bonechi; M. Bongi; S. Bottai; D. Fedele; P. Papini; S. Ricciarini; P. Spillantini; E. Taddei; E. Vannuccini; G. Barbarino; D. Campana; R. Carbone; G. De Rosa; G. Osteria; M. Boezio; V. Bonvicini; E. Mocchiutti; A. Vacchi; G. Zampa; N. Zampa; A. Bruno; F. S. Cafagna; Marco Ricci; Petter Hofverberg; Mark Pearce; Per Carlson; Edward Bogomolov; S. Yu. Krutkov; N. N. Nikonov; G. I. Vasilyev; Wolfgang Menn; Manfred Simon; Arkady M. Galper; Lubov Grishantseva; Sergey Koldashov; Alexey Leonov; Vladimir V. Mikhailov; Sergey A. Voronov; Yuri T. Yurkin; Valeri G. Zverev; Galina A. Bazilevskaya; Alexander N. Kvashnin; Osman Maksumov; Yuri Stozhkov

2009-01-01

237

The highest energy cosmic rays: Observations  

NASA Astrophysics Data System (ADS)

Observations of cosmic ray air showers with energies above 0.1 EeV (1017 eV) are key to understanding where the highest energy cosmic rays originate, how they acquire their energy, what types of particles they are, and also the nature of their ultra-high-energy hadronic interactions at the top of the atmosphere. Prominent features of the energy spectrum have now been established, although some difference remains in energy normalization between results from different observatories. A distinct ankle is present near 4 EeV, and a GZK-like downturn is evident above about 30 EeV. Well above that GZK threshold, there have been tantalizing indications of clustering of arrival directions and correlation with catalogs of local matter, but no anisotropy has been independently confirmed so far at any energy above 0.1 EeV. With 99% confidence, the dipole anisotropy is less than 2% for energies just below 1 EeV, as measured in right ascension from the southern hemisphere. Moreover, no discrete source of neutral particles has been discovered and astrophysically interesting upper limits have been derived. Although the present upper limits on the diffuse intensities of photons and neutrinos do not constrain typical models of GZK production, they have eliminated most top-down models in which cosmic rays originate through the annihilation or decay of supermassive particles. The vast majority of cosmic rays must be protons and other charged nuclei. Data from different observatories have led to inconsistent inferences about the relative abundances of primary mass groups and the dependence of the composition on energy. The effective proton-air interaction cross section has been measured at EeV energies and is in agreement with conventional extrapolations obtained from measurements at collider energies.

Sommers, Paul

2013-02-01

238

Cosmic ray gradients in the outer heliosphere  

NASA Technical Reports Server (NTRS)

Launched in 1972 and 1973 respectively, the Pioneer 10 and 11 spacecraft are now probing the outer heliosphere on their final escape from the sun. The data in this paper extend for almost an entire solar cycle from launch to early 1983, when Pioneer 10 was at a heliocentric distance of 29 AU and Pioneer 11, 13 AU. The UCSD instruments on board were used to study the gradient, and to look at the time and spatial variations of the cosmic ray intensities.

Fillius, W.; Wake, B.; Ip, W.-H.; Axford, I.

1983-01-01

239

Possible cosmological origin of the ultra high energy cosmic rays  

SciTech Connect

Using improved spectrum evolution results for nucleons propagation through the 3/sup 0/K microwave background we present a model of the UHE cosmic rays, above 10/sup 18/ eV, assuming a universal cosmological component associated with bright phase activity and a semi-local component associated with the Virgo cluster. The results for the spectrum and anisotropy are in good agreement with the Haverah Park EAS observations. An unambiguous and potentially detectable electron neutrino spectrum is derived.

Hill, C.T.

1984-04-01

240

Cosmic rays in the heliosphere: Observations  

NASA Astrophysics Data System (ADS)

This contribution to the 100th commemoration of the discovery of cosmic rays (6-8 August, 2012 in Bad Saarow, Germany) is about observations of those cosmic rays that are sensitive to the structure and the dynamics of the heliosphere. This places them in the energy range of 107-1010 eV. For higher energies the heliosphere becomes transparent; below this energy range the particles become strictly locked into the solar wind. Rather than give a strict chronological development, the paper is divided into distinct topics. It starts with the Pioneer/Voyager missions to the outer edges of the heliosphere, because the most recent observations indicate that a distinct boundary of the heliosphere might have been reached at the time of the meeting. Thereafter, the Ulysses mission is described as a unique one because it is still the only spacecraft that has explored the heliosphere at very high latitudes. Next, anomalous cosmic rays, discovered in 1972-1974, constitute a separate component that is ideally suited to study the acceleration and transport of energetic particles in the heliosphere. At this point the history and development of ground-based observations is discussed, with its unique contribution to supply a stable, long-term record. The last topic is about solar energetic particles with energies up to ?1010 eV.

Moraal, Harm

2014-01-01

241

Cosmic rays X. The cosmic ray knee and beyond: diffusive acceleration at oblique shocks  

NASA Astrophysics Data System (ADS)

Our purpose is to evaluate the rate of the maximum energy and the acceleration rate that cosmic rays acquire in the non-relativistic diffusive shock acceleration as it could apply during their lifetime in various astrophysical sites, where highly oblique shocks exist. We examine numerically (using Monte-Carlo simulations) the effect of the diffusion coefficients on the energy gain and the acceleration rate, by testing the role between the obliquity of the magnetic field to the shock normal, and the significance of both perpendicular cross-field diffusion and parallel diffusion coefficients to the acceleration rate. We find (and justify previous analytical work - Jokipii 1987, ApJ, 313, 842) that in highly oblique shocks the smaller the perpendicular diffusion gets compared to the parallel diffusion coefficient values, the greater the energy gain of the cosmic rays to be obtained. An explanation of the cosmic ray spectrum in high energies, between 1015 eV and about 1018 eV is claimed, as we estimate the upper limit of energy that cosmic rays could gain in plausible astrophysical regimes; interpreted by the scenario of cosmic rays which are injected by three different kind of sources, (a) supernovae which explode into the interstellar medium, (b) Red Supergiants, and (c) Wolf-Rayet stars, where the two latter explode into their pre-supernovae winds.

Meli, A.; Biermann, P. L.

2006-08-01

242

Ultra-high energy cosmic rays: Observational results  

NASA Astrophysics Data System (ADS)

The study of ultra-high energy cosmic rays has experienced a jump in statistics as well as improved instrumentation. The number of detected cosmic rays has increased by more than a factor of ten over the past decade, and measurements are checked using multiple detection techniques. The energy spectrum clearly has a spectral hardening known as "the ankle" and also a "GZK-like" downturn above 1019.5 eV. Evidence of trans-GZK arrival directions correlating with AGNs and/or the large-scale matter distribution within the GZK sphere has not been confirmed so far. More data are needed to verify and understand that anisotropy. A search for neutron fluxes from discrete sources in the Galaxy has yielded no detection, and the neutron flux upper limits constrain models for EeV proton production. Additional constraint has come from measuring the first harmonic in right ascension of the cosmic ray arrival directions, which has yielded upper limits below 2% at energies up to 2 EeV.

Sommers, Paul

2012-12-01

243

Cosmic X-ray physics  

NASA Astrophysics Data System (ADS)

The soft X-ray sky survey data are combined with the results from the UXT sounding rocket payload. Very strong constraints can then be placed on models of the origin of the soft diffuse background. Additional observational constraints force more complicated and realistic models. Significant progress was made in the extraction of more detailed spectral information from the UXT data set. Work was begun on a second generation proportional counter response model. The first flight of the sounding rocket will have a collimator to study the diffuse background.

McCammon, D.; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1987-07-01

244

Cosmic X-ray physics  

NASA Technical Reports Server (NTRS)

The soft X-ray sky survey data are combined with the results from the UXT sounding rocket payload. Very strong constraints can then be placed on models of the origin of the soft diffuse background. Additional observational constraints force more complicated and realistic models. Significant progress was made in the extraction of more detailed spectral information from the UXT data set. Work was begun on a second generation proportional counter response model. The first flight of the sounding rocket will have a collimator to study the diffuse background.

Mccammon, D.; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1987-01-01

245

GEANT4 Simulation of a Cosmic Ray Muon Tomography System With Micro-Pattern Gas Detectors for the Detection of High Materials  

Microsoft Academic Search

Muon tomography (MT) based on the measurement of multiple scattering of atmospheric cosmic ray muons traversing shipping containers is a promising candidate for identifying threatening high-Z materials. Since position-sensitive detectors with high spatial resolution should be particularly suited for tracking muons in a MT application, we propose to use compact micro-pattern gas detectors, such as gas electron multipliers (GEMs), for

Marcus Hohlmann; Patrick Ford; Kondo Gnanvo; Jennifer Helsby; David Pena; Richard Hoch; Debasis Mitra

2009-01-01

246

Radio Emission from Cosmic Ray Air Showers  

NASA Astrophysics Data System (ADS)

Charged particles with energies ranging from a few times 10^6 eV up to > 10^20 eV continuously impinge on the earth as so-called "cosmic rays". Their study constitutes an important field of research in both astronomy and particle physics, and some cosmic ray related effects even have significance for the public's every-day life. Radio emission from cosmic ray air showers offers the opportunity to use radio observations as an additional powerful observing technique in cosmic ray research, thereby building a bridge between astroparticle physics and radio astronomy. As a necessary prerequisite, a detailed theoretical analysis of the processes responsible for the radio emission has to be performed. In this thesis, we analyse the emission in the scheme of "coherent geosynchrotron radiation" emitted by electron-positron pairs created in the air shower cascade as they are deflected in the earth's magnetic field. We first perform an analytic calculation of the emission based on realistic parametrisations of the particle distributions in the air shower. The analytic approach allows us to gain a solid understanding of general emission features and the coherence effects arising from the different physical scales present in the air shower. We compare our predictions with the available historical data and find that geosynchrotron radiation can indeed explain the emission. Afterwards, we conceive and implement a sophisticated Monte Carlo code, performing the calculation with increased precision and taking into account a more realistic air shower model. We describe and test the concepts envisaged to allow a high-precision modelling of realistic air showers on standard computer hardware and compare the Monte Carlo results with the analytic calculations to ensure the correctness of our modelling efforts. In a last step, we use our Monte Carlo code to simulate a large number of air showers in order to study the effect of important air shower parameters and geometries on the associated radio emission. Our main result is a parametrisation formula relating the radio emission characteristics directly to important air shower and observer parameters such as the air shower geometry, the primary particle energy, the depth of the shower maximum, the observer distance from the shower centre, and the observing frequency. With this analysis, we build the foundation for the interpretation of experimental measurements of radio emission from extensive air showers and thus make a great step forward in the establishment of radio observations as an additional observing technique in cosmic ray research.

Huege, Tim

2004-12-01

247

The intergalactic propagation of ultrahigh energy cosmic ray nuclei  

SciTech Connect

We investigate the propagation of ultra-high energy cosmic ray nuclei (A = 1-56) from cosmologically distant sources through the cosmic radiation backgrounds. Various models for the injected composition and spectrum and of the cosmic infrared background are studied using updated photodisintegration cross-sections. The observational data on the spectrum and the composition of ultra-high energy cosmic rays are jointly consistent with a model where all of the injected primary cosmic rays are iron nuclei (or a mixture of heavy and light nuclei).

Hooper, Dan; /Fermilab; Sarkar, Subir; /Oxford U., Theor. Phys.; Taylor, Andrew M.; /Oxford U.

2006-08-01

248

Possible Association of Ultra--High-Energy Cosmic-Ray Events with Strong Gamma-Ray Bursts  

NASA Astrophysics Data System (ADS)

We point out that each of the error boxes of the two highest energy cosmic-ray shower events known overlaps with that of a strong gamma-ray burst (GRB). The GRBs precede the cosmic rays by 5.5 and 11 months, respectively. In one case the strongest known cosmic ray is paired with the strongest gamma-ray burst in the BATSE catalog. The probability of this occurring by chance seems rather small. Without building on post factum statistics, we think the above is remarkable enough to suggest that the cosmic-ray and gamma-ray burst were produced by the same outburst. A time delay, and a small positional disparity, are expected, since the trajectory of a charged cosmic-ray particle is wriggled by intervening magnetic fields. We estimate that the Galaxy's field alone may produce a delay of the order observed. With similar energies going into gamma rays and cosmic rays, we expect only a few times 10% of the strongest GRBs to be followed by a detection of an ultra--high-energy (E > 1020 eV) cosmic ray in existing experiments. We discuss some of the implications that follow if such an association is confirmed. For example, the upper limit on the distance of the cosmic-ray source, combined with a much better determined position of the gamma-ray burst source, reduces greatly the volume in which to look for an optical counterpart. The need to produce ultra--high-energy cosmic rays in the GRB source imposes additional constraints on the physical conditions in it. There is also useful information in the time delay regarding, e.g., intergalactic magnetic fields.

Milgrom, Mordehai; Usov, Vladimir

1995-08-01

249

Pointlike gamma ray sources as signatures of distant accelerators of ultrahigh energy cosmic rays.  

PubMed

We discuss the possibility of observing distant accelerators of ultrahigh energy cosmic rays in synchrotron gamma rays. Protons propagating away from their acceleration sites produce extremely energetic electrons during photopion interactions with cosmic microwave background photons. If the accelerator is embedded in a magnetized region, these electrons will emit high energy synchrotron radiation. The resulting synchrotron source is expected to be pointlike, steady, and detectable in the GeV-TeV energy range if the magnetic field is at the nanoGauss level. PMID:16384444

Gabici, Stefano; Aharonian, Felix A

2005-12-16

250

Pierre Auger Enhancements: Transition from Galactic to Extragalactic Cosmic Ray Sources  

SciTech Connect

The Pierre Auger Collaboration has decided to include detector enhancements in order to have unitary detection efficiencies down to 1017 eV in cosmic rays detection. These enhancements consist in high elevation telescopes and an infill area with both surface detectors and underground muon counters thus allowing a detailed study of the spectrum region where the cosmic rays sources are assumed to change from galactic to extragalactic origins.

Etchegoyen, A. [Laboratorio Tandar - Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Universidad Tecnologica Nacional, Regional Buenos Aires, Buenos Aires (Argentina); Melo, D.; Supanitsky, A. D. [Laboratorio Tandar - Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Medina, M. C. [Laboratorio Tandar - Comision Nacional de Energia Atomica, Buenos Aires (Argentina); CONICET. Buenos Aires (Argentina)

2007-06-19

251

FAMOUS - A prototype silicon photomultiplier telescope for the fluorescence detection of ultra-high-energy cosmic rays  

NASA Astrophysics Data System (ADS)

Due to their high photon detection efficiency, silicon photomultipliers (SiPMs) promise to increase the sensitivity of today's fluorescence telescopes which use photomultiplier tubes to detect light originating from extensive air showers. On the other hand, drawbacks like a small sensitive area, a strong temperature dependence, a high noise rate and a reduced dynamic range have to be managed. We present plans for FAMOUS, a prototype fluorescence telescope using SiPMs and a special light collecting optical system of Winston cones to increase the sensitive area. The prototype will make use of a Fresnel lens. For several different types of SiPMs we measured their characteristics. Moreover, we will present the R&D in compact modular electronics using photon counting techniques. An evaluation of the performance of the optical telescope design is performed by means of a full detector simulation.

Stephan, Maurice; Assis, Pedro; Brogueira, Pedro; Ferreira, Miguel; Hebbeker, Thomas; Lauscher, Markus; Mendes, Luís; Meurer, Christine; Middendorf, Lukas; Pimenta, Mário; Schumacher, Johannes

2013-06-01

252

Modulation of cosmic ray precipitation related to climate  

NASA Astrophysics Data System (ADS)

High energy cosmic rays may influence the formation of clouds and thus impact weather and climate. Due to systematic solar wind changes, the intensity of cosmic rays incident on the magnetopause has decreased markedly during this century. The pattern of cosmic ray precipitation through the magnetosphere to the upper troposphere has also changed. Early in the century, the part of the troposphere open to cosmic rays of all energies was typically confined to a relatively small high-latitude region. As the century progressed the size of this region increased by over 25% and there was a 6.5° equatorward shift in the yearly averaged latitudinal position of the subauroral region in which cloud cover has been shown to be cosmic ray flux dependent. We suggest these changes in cosmic ray intensity and latitude distribution may have influenced climate change during the last 100 years.

Feynman, J.; Ruzmaikin, A.

1999-07-01

253

Can cosmic neutrinos be detected with superconductors  

SciTech Connect

The development of techniques for the experimental detection of cosmic neutrinos would be of great importance the both astrophysics and particle physics. In this paper ideas based on the coherent response of conducting materials to long-wavelength cosmic or galactic neutrinos, via the weak neutral current interaction are discussed. The necessity to consider the refraction of neutrino waves by the conduction electrons as an independent process leads to the absence of recoil electric currents to first order in G for a uniform neutrino flux. As a result of this, a recently-published suggestion (Opher, 1982) for the detection of cosmic (and also solar) neutrinos with small volumes of superconducting material is shown to be fallacious. Superconducting detectors based on the very small forces of order G2 would be possible in principle, but no practically feasible scheme has yet been suggested. Some basic questions concerning the interaction of neutrinos with a closed superconducting circuit also require more detailed study. 15 references.

Lewin, J.D.; Smith, P.F.

1984-01-01

254

The isotopic composition of cosmic-ray calcium  

NASA Technical Reports Server (NTRS)

We find that the relative abundance of cosmic ray calcium isotopes in the cosmic-ray source are very similar to those found in solar-system material, in spite of the fact that different types of stars are thought to be responsible for producing these two isotopes. This observation is consistent with the view that cosmic rays are derived from a mixed sample of interstellar matter.

Wiedenbeck, M. E.; George, J. S.; Binns, W. R.; Christian, E. R.; Cummings, A. C.; Davis, A. J.; Israel, M. H.; Leske, R. A.; Mewaldt, R. A.; Stone, E. C.; Rosenvinge, T. T. von

2001-01-01

255

Maximum cosmic ray energies and the shock acceleration mechanism  

NASA Astrophysics Data System (ADS)

The Ultra High Energy Cosmic Rays have a flux which is about one particle per square km per century, at an energy of ~=1020 eV. Shocks in astrophysical environments, such as in jets of Active Galactic Nuclei, seem to be the sources of these cosmic rays. In this selected talk I will briefly present and discuss the efficiency of the first order Fermi acceleration mechanism in extragalactic astrophysical shocks, focusing at the highest cosmic ray energies.

Meli, A.

2010-06-01

256

Cosmological Cosmic-Ray Contribution to the Extragalactic Gamma-Ray Background  

NASA Astrophysics Data System (ADS)

The extragalactic gamma-ray background measured by The Fermi Gamma-Ray Space Telescope is substantially different from previous measurements. Fermi has clarified that the dominant emission mechanism comes from cosmic-ray interactions with interstellar gas in normal galaxies. We present a constraint of cosmological cosmic-ray contribution to the extragalactic gamma-ray background. Even though normal galaxies seem to be dominant component, they still fall short to explain measured gamma-ray background at highest energies, thus another source has to be taken into consideration. Using models of evolution of cosmic accretion shock, we calculate pionic gamma-ray source-function for cosmological cosmic rays independent of redshift. We show that cosmological cosmic rays could even dominate the extragalactic gamma-ray background at highest energies. We also show that measured background can well be explained by these two cosmic-ray components - normal star-forming galaxies and cosmological cosmic rays.

Ciprijanovic, A.

2012-12-01

257

Cosmic Ray Impact on Extrasolar Earth-Like Planets in Close-in Habitable Zones  

Microsoft Academic Search

Because of their different origins, cosmic rays can be subdivided into galactic cosmic rays and solar\\/stellar cosmic rays. The flux of cosmic rays to planetary surfaces is mainly determined by two planetary parameters: the atmospheric density and the strength of the internal magnetic moment. If a planet exhibits an extended magnetosphere, its surface will be protected from high-energy cosmic ray

J.-M. Grießmeier; A. Stadelmann; U. Motschmann; N. K. Belisheva; H. Lammer; H. K. Biernat

2005-01-01

258

Cosmic-ray record in solar system matter  

SciTech Connect

The energetic nuclei in cosmic rays interact with meteoroids, the moon, planets, and other solar system matter. The nucleides and heavy nuclei tracks produced by the cosmic-ray particles in these targets contain a wealth of information about the history of the objects and temporal ans spatial variations in the particle fluxes. Most lunar samples and many meteorites ahve complex histories of cosmic-ray exposure from erosion, gardening, fragmentation, orbital changes, and other processes. There appear to be variations in the past fluxes of solar particles, and possibly also galactic cosmic rays, on time scales of 10/sup 4/ to 10/sup 7/ years.

Reedy, R.C. (Los Alamos National Lab., NM); Arnold, J.R.; Lal, D.

1983-01-14

259

Laboratory investigations on the origins of cosmic rays  

NASA Astrophysics Data System (ADS)

We report our recent efforts on the experimental investigations related to the origins of cosmic rays. The origins of cosmic rays are long standing open issues in astrophysics. The galactic and extragalactic cosmic rays are considered to be accelerated in non-relativistic and relativistic collisionless shocks in the universe, respectively. However, the acceleration and transport processes of the cosmic rays are not well understood, and how the collisionless shocks are created is still under investigation. Recent high-power and high-intensity laser technologies allow us to simulate astrophysical phenomena in laboratories. We present our experimental results of collisionless shock formations in laser-produced plasmas.

Kuramitsu, Y.; Sakawa, Y.; Morita, T.; Ide, T.; Nishio, K.; Tanji, H.; Aoki, H.; Dono, S.; Gregory, C. D.; Waugh, J. N.; Woolsey, N.; Dizière, A.; Pelka, A.; Ravasio, A.; Loupias, B.; Koenig, M.; Pikuz, S. A.; Li, Y. T.; Zhang, Y.; Liu, X.; Y Zhong, J.; Zhang, J.; Gregori, G.; Nakanii, N.; Kondo, K.; Mori, Y.; Miura, E.; Kodama, R.; Kitagawa, Y.; Mima, K.; Tanaka, K. A.; Azechi, H.; Moritaka, T.; Matsumoto, Y.; Sano, T.; Mizuta, A.; Ohnishi, N.; Hoshino, M.; Takabe, H.

2012-12-01

260

Acoustic instability driven by cosmic-ray streaming  

NASA Technical Reports Server (NTRS)

We study the linear stability of compressional waves in a medium through which cosmic rays stream at the Alfven speed due to strong coupling with Alfven waves. Acoustic waves can be driven unstable by the cosmic-ray drift, provided that the streaming speed is sufficiently large compared to the thermal sound speed. Two effects can cause instability: (1) the heating of the thermal gas due to the damping of Alfven waves driven unstable by cosmic-ray streaming; and (2) phase shifts in the cosmic-ray pressure perturbation caused by the combination of cosmic-ray streaming and diffusion. The instability does not depend on the magnitude of the background cosmic-ray pressure gradient, and occurs whether or not cosmic-ray diffusion is important relative to streaming. When the cosmic-ray pressure is small compared to the gas pressure, or cosmic-ray diffusion is strong, the instability manifests itself as a weak overstability of slow magnetosonic waves. Larger cosmic-ray pressure gives rise to new hybrid modes, which can be strongly unstable in the limits of both weak and strong cosmic-ray diffusion and in the presence of thermal conduction. Parts of our analysis parallel earlier work by McKenzie & Webb (which were brought to our attention after this paper was accepted for publication), but our treatment of diffusive effects, thermal conduction, and nonlinearities represent significant extensions. Although the linear growth rate of instability is independent of the background cosmic-ray pressure gradient, the onset of nonlinear eff ects does depend on absolute value of DEL (vector differential operator) P(sub c). At the onset of nonlinearity the fractional amplitude of cosmic-ray pressure perturbations is delta P(sub C)/P(sub C) approximately (kL) (exp -1) much less than 1, where k is the wavenumber and L is the pressure scale height of the unperturbed cosmic rays. We speculate that the instability may lead to a mode of cosmic-ray transport in which plateaus of uniform cosmic-ray pressure are separated by either laminar or turbulent jumps in which the thermal gas is subject to intense heating.

Begelman, Mitchell C.; Zweibel, Ellen G.

1994-01-01

261

Gamma-ray bursters as sources of cosmic rays  

NASA Astrophysics Data System (ADS)

From the little we know of the physical conditions in ?-ray bursters, it seems that they are potentially effective in the acceleration of high-energy cosmic rays (CRs), especially if the bursters are at cosmological distances. We find that, with the observed statistics and fluxes of ?-ray bursts, cosmological bursters may be an important source of cosmic rays in two regions of the observed spectrum: (1) At the very-high-energy end ( E > 10 19 eV), where CRs must be of extragalactic origin. (2) Around and above the spectral feature that has been described as a bump and/or a knee, which occurs around 10 15 eV. The occasional bursters that occur inside the Galaxy — about once in a few hundred thousand years if burst emission is isotropic; more often, if it is beamed — could maintain the density of galactic cosmic rays at the observed level in this range. These two energy ranges might correspond to two typical CR energy scales characteristic of bursters: one pertinent to CR acceleration due to interaction of a magnetized-fireball front with an ambient medium; the other to acceleration in the fireball itself (e.g. shock acceleration).

Milgrom, Mordehai; Usov, Vladimir

1996-04-01

262

Radiation Hazard from Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

Space radiation is a major hazard to astronauts in long-duration human space explosion. Astronauts are exposed to an enormous amount of radiation during their missions away from the Earth in outer space. Deep space is a rich environment of protons, gamma rays and cosmic rays. A healthy 40 years old man staying on Earth away from large doses of radiation stands a 20% chance of dying from cancer. If the same person travels into a 3- year Mars mission, the added risk should increase by 19%. This indicates that there is 39% chance of having cancer after he comes back to Earth. Female astronaut chances to get cancer is even almost double the above percentage. The greatest threat to astronauts en route to the red planet is galactic cosmic rays (GCR). GCRs penetrate through the skin of spaceships and people like tiny firearm bullets, breaking the strands of DNA molecules, damaging genes, and killing cells. Understanding the nature of the GCRs, their effect on biological cells, and their interactions with different shielding materials is the key point to shield against them in long space missions. In this paper we will present a model to evaluate the biological effects of GCRs and suggestion different ways to shield against them.

Farahat, Ashraf

2006-03-01

263

The interplanetary transport of solar cosmic rays  

NASA Technical Reports Server (NTRS)

Numerical solutions are presented for the propagation of solar cosmic rays in interplanetary space, including the effects of pitch-angle scattering and adiabatic focusing. The intensity-time profiles can be well fitted by a simple radial spatial diffusion equation with scattering mean-free path lambda(fit). The radial mean-free path so obtained is significantly larger than the true scattering mean-free path for low-rigidity particles due to both adiabatic focusing and the inapplicability of the diffusive approximation early in the event. The well-known discrepancy between lambda(fit) and the theoretical predictions may be resolved by these calculations.

Gombosi, T. I.; Owens, A. J.

1980-01-01

264

Unusual anisotropic wave trains in cosmic rays  

NASA Astrophysics Data System (ADS)

Several workers have attempted to find out the possible origin of the "high amplitude wave trains" of enhanced diurnal variation of cosmic rays and to develop a suitable realistic theoretical model that can explain the different harmonics in individual days. The various observed harmonics of the cosmic-ray variation may be understood on a unified basis if the free-space cosmic-ray anisotropy is non-sinusoidal in form. The major objective of this paper is to study the first three harmonics of high-amplitude wave trains of cosmic-ray intensity over the period 1981-1994 for Deep River neutron monitoring station. The main characteristic of these events is that the high-amplitude wave trains show a maximum intensity of diurnal component in a direction earlier than 18:00 h/co-rotational direction. It is noteworthy that the amplitude significantly enhanced and the phase remains in the co-rotational direction during the years close to solar-activity maximum for first harmonic. Significant deviations have been observed in the semi-diurnal amplitude after the onset of solar-activity maximum. This leads us to conclude that the amplitude as well as direction of the first harmonic and the amplitude of second harmonic are correlated with solar-activity cycle during these HAEs. The amplitude and phase of all the three harmonics (diurnal/semi-diurnal/tri-diurnal) are not found to depend on the polarity of Bz component of interplanetary magnetic field for long-term variation. The occurrence of high-amplitude events is dominant for the positive polarity of Bz component of IMF. The occurrence of HAEs is dominant during the period of average solar-wind velocity, but their occurrence during HSSWSs cannot be denied. The possibility of occurrence of these events is more during the periods of co-rotating streams. The occurrence of HAE is dominant when Dst-index remains negative and this point is not reported earlier in the litterature. All the high amplitude events occurred, when geomagnetic activity index, Ap, remains ?20.

Mishra, Rajesh K.; Mishra, Rekha Agarwal

2007-11-01

265

Turbulent heating in solar cosmic ray theory  

NASA Technical Reports Server (NTRS)

The heating of minor ions in solar flares by wave-wave-particle interaction with Langmuir waves, or ion acoustic waves, can be described by a diffusion equation in velocity-space for the particle distribution function. The dependence of the heating on the ion charge and mass, and on the composition of the plasma, is examined in detail. It is found that the heating mechanisms proposed by Ibragimov and Kocharov cannot account for the enhanced abundances of heavy elements in the solar cosmic rays.

Weatherall, J.

1983-01-01

266

Model approximation of cosmic ray spectrum  

NASA Astrophysics Data System (ADS)

An analytical model which generalizes the equations describing the intensity of galactic cosmic rays (CR), including both processes, making it applicable in the inner heliosphere (where energy losses dominate) and outer heliosphere (influenced primarily by convection-diffusion processes) is derived. By a suitable choice of a parameter, the proposed model turns into two approximations: solution close to "force-field" model (describing the energy losses of CR in the inner heliosphere) and "convection-diffusion" equation (giving the reduction of CR intensity in the outer heliosphere). A mathematical relation between parameters in the proposed model and the modulation parameter ? is derived.

Buchvarova, M.; Velinov, P. I. Y.; Buchvarov, I.

2011-03-01

267

High energy cosmic ray iron spectrum experiment  

NASA Technical Reports Server (NTRS)

An instrument containing a gas Cerenkov counter and an iron ionization spectrometer was constructed in order to measure the cosmic-ray iron spectrum to 300 GeV/nucleon. Trajectories of particles were determined by entopistic or position-determining scintillator systems. The geometric factors with and without the gas Cerenkov counter were 0.3 and 0.6 sq m-ster, respectively. The instrument was successfully flown in June 1976 without the spectrometer and in October 1976 with the spectrometer from Palestine, Texas. The June flight yielded 14.5 h of data; the October flight, 25 h.

Arens, J. F.; Balasubrahmanyan, V. K.; Ormes, J. F.; Schmidt, W. K. H.; Simon, M.; Spiegelhauer, H.

1978-01-01

268

Galactic origin of cosmic rays I  

SciTech Connect

The theoretical basis for the supernova envelope shock origin of cosmic rays is reviewed. The theoretical explanation of the SN Type I light curve requires the ejection of a relativistic mass fraction. The criterion of the adiabatic decelleration by Alfven wave trapping neither applies in theory, when ..beta.. > 1, or practice, the Starfish high altitude nuclear explosion experiment. Arguments of delayed acceleration due to K-capture are not applicable to SN ejecta because a period of prompt recombination exists before subsequent stripping in propagation.

Colgate, S.A.

1981-01-01

269

The source abundances of galactic cosmic rays  

NASA Technical Reports Server (NTRS)

The galactic cosmic ray source abundances have been determined from two complete datasets, one at low and the other at high energy. For both exponential and truncated exponential pathlength distributions (PLD), the two sets of source abundances show significant differences for the primary elements, i.e., the Fe/O ratio. An energy dependent PLD reduces but does not eliminate the discrepancy, and this may indicate an energy dependence in the source composition. New source abundances for Na, P, Cl, Ca, and Mn are derived.

Dwyer, R. D.; Garcia-Munoz, M.; Guzik, T. G.; Meyer, P.; Simpson, J. A.; Wefel, J. P.

1982-01-01

270

Transition from Galactic to extragalactic cosmic rays and cosmic ray anisotropy  

NASA Astrophysics Data System (ADS)

This talk based on results of ref. [1], where we constrain the energy at which the transition from Galactic to extragalactic cosmic rays occurs by computing the anisotropy at Earth of cosmic rays emitted by Galactic sources. Since the diffusion approximation starts to loose its validity for E/Z ? 10(16-17) eV, we propagate individual cosmic rays using Galactic magnetic field models and taking into account both their regular and turbulent components. The turbulent field is generated on a nested grid which allows spatial resolution down to fractions of a parsec. If the primary composition is mostly light or intermediate around E ˜ 1018 eV, the transition at the ankle is ruled out, except in the unlikely case of an extreme Galactic magnetic field with strength >10 ?G. Therefore, the fast rising proton contribution suggested by KASCADE-Grande data between 1017 eV and 1018 eV should be of extragalactic origin. In case heavy nuclei dominate the flux at E > 1018 eV, the transition energy can be close to the ankle, if Galactic cosmic rays are produced by sufficiently frequent transients as e.g. magnetars.

Giacinti, G.; Kachelrieß, M.; Semikoz, D. V.; Sigl, G.

2013-06-01

271

Common solution to the cosmic ray anisotropy and gradient problems.  

PubMed

Multichannel cosmic ray spectra and the large scale cosmic ray anisotropy can hardly be made compatible in the framework of conventional isotropic and homogeneous propagation models. These models also have problems explaining the longitude distribution and the radial emissivity gradient of the ?-ray Galactic interstellar emission. We argue here that accounting for a physically motivated correlation between the cosmic ray escape time and the spatially dependent magnetic turbulence power can naturally solve both problems. Indeed, by exploiting this correlation we find propagation models that fit a wide set of cosmic ray spectra, and consistently reproduce the cosmic ray anisotropy in the energy range 10(2)-10(4) GeV and the ?-ray longitude distribution recently measured by Fermi-LAT. PMID:23003236

Evoli, Carmelo; Gaggero, Daniele; Grasso, Dario; Maccione, Luca

2012-05-25

272

Lunar surface cosmic ray experiment S-152, Apollo 16  

NASA Technical Reports Server (NTRS)

This investigation was directed at determining the energy spectra and abundances of low energy heavy cosmic rays (0.03 E or = 150 MeV/nucleon). The cosmic rays were detected using plastic and glass particle track detectors. Particles emitted during the 17 April 1972 solar flare dominated the spectra for energies below about 70 MeV/nucleon. Two conclusions emerge from the low energy data: (1) The differential energy spectra for solar particles vary rapidly for energies as low as 0.05 MeV/nucleon for iron-group nuclei. (2) The abundance ratio of heavy elements changes with energy at low energies; heavy elements are enhanced relative to higher elements increasingly as the energy decreases. Galactic particle fluxes recorded within the spacecraft are in agreement with those predicted taking into account solar modulation and spacecraft shielding. The composition of the nuclei at energies above 70 MeV/nucleon imply that these particles originate outside the solar system and hence are galactic cosmic rays.

Fleischer, R. L.; Hart, H. R., Jr.; Carter, M.; Comostock, G. M.; Renshaw, A.; Woods, R. T.

1973-01-01

273

Ultrahigh energy cosmic rays from topological defects-cosmic strings, monopoles, necklaces, and all that  

Microsoft Academic Search

The topological defect scenario of origin of the observed highest energy cosmic rays is reviewed. Under a variety of circumstances, topological defects formed in the early Universe can be sources of very massive particles in the Universe today. The decay products of these massive particles may be responsible for the observed highest energy cosmic ray particles above 1020 eV. Some

Pijushpani Bhattacharjee

1998-01-01

274

Ultrahigh Energy Cosmic Rays from Topological Defects — Cosmic Strings, Monopoles, Necklaces, and All That1  

Microsoft Academic Search

The topological defect scenario of origin of the observed highest energy cosmic rays is reviewed. Under a variety of circumstances, topological defects formed in the early Universe can be sources of very massive particles in the Universe today. The decay products of these massive particles may be responsible for the observed highest energy cosmic ray particles above 1020 eV. Some

Pijushpani Bhattacharjee

275

Calculations for cosmic axion detection  

NASA Technical Reports Server (NTRS)

Calculations are presented, using properly nomalized couplings and masses for Dine-Fischler-Srednicki axions, of power rates and signal temperatures for axion-photon conversion in microwave cavities. The importance of the galactic-halo axion line shape is emphasized. Spin-coupled detection as an alternative to magnetic-field-coupled detection is mentioned.

Krauss, L.; Moody, J.; Wilczek, F.; Morris, D. E.

1985-01-01

276

REal-time COsmic Ray Database (RECORD)  

NASA Astrophysics Data System (ADS)

In this paper we present a first distributed REal-time COsmic Ray Database (RECORD). The aim of the project is to develop a unified database with data from different neutron monitors collected together, in unified format and to provide a user with several commonly used data access methods. The database contains not only original cosmic ray data but also auxiliary data necessary for scientific data analysis. Currently the database includes Lomn.Stit, Moscow, Oulu; Tixie Bay, Yakutsk stations. The main database server is located in IKFIA SB RAS (Yakutsk) but there will be several mirrors of the database. The database and all its mirrors are up dated on the nearly real-time (1 hour) basis. The data access software includes WWW-interface, Perl scripts and C library, which may be linked to a user program. Most of frequently used functions are implemented to make it operable to users without SQL language knowledge. A draft of the data representation standard is suggested, based on common practice of neutron monitor community. The database engine is freely distributed open-sourced PostgreSQL server coupled with a set of replication to ols developed at Bio engineering division of the IRCCS E.Medea, Italy.

Usoskin, I.; Kozlov, Valery; Ksenofontov, Leonid, Kudela, Karel; Starodubtsev, Sergei; Turpanov, Alexey; Yanke, Victor

2003-07-01

277

Statistical properties of the time histories of cosmic gamma-ray bursts detected by the BATSE experiment of the Compton gamma-ray observatory  

NASA Technical Reports Server (NTRS)

The main scientific objectives of the project were: (1) Calculation of average time history for different subsets of BATSE gamma-ray bursts; (2) Comparison of averaged parameters and averaged time history for different Burst And Transient Source Experiments (BASTE) Gamma Ray Bursts (GRB's) sets; (3) Comparison of results obtained with BATSE data with those obtained with APEX experiment at PHOBOS mission; and (4) Use the results of (1)-(3) to compare current models of gamma-ray bursts sources.

Sagdeev, Roald

1995-01-01

278

Ultrahigh Energy Cosmic Rays: Old Physics or New Physics?  

NASA Technical Reports Server (NTRS)

We consider the advantages of and the problems associated with hypotheses to explain the origin of ultrahigh energy cosmic rays (UHECR: E greater than 10 EeV) and the "trans-GZK" cosmic rays (TGZK: E greater than 100 EeV) both through "old physics" (acceleration in cosmic sources) and "new physics" (new particles, topological defects, fat neutrino cross sections, Lorentz invariance violation).

Stecker, F. W.

2004-01-01

279

Effect of energy deposited by cosmic-ray particles on interferometric gravitational wave detectors  

SciTech Connect

We investigated the noise of interferometric gravitational wave detectors due to heat energy deposited by cosmic-ray particles. We derived a general formula that describes the response of a mirror against a cosmic-ray passage. We found that there are differences in the comic-ray responses (the dependence of temperature and cosmic-ray track position) in cases of interferometric and resonant gravitational wave detectors. The power spectral density of vibrations caused by low-energy secondary muons is 100 times smaller than the goal sensitivity of future second-generation interferometer projects, such as LCGT and Advanced LIGO. The arrival frequency of high-energy cosmic-ray muons that generate enough large showers inside mirrors of LCGT and Advanced LIGO is one per a millennium. We also discuss the probability of exotic-particle detection with interferometers.

Yamamoto, Kazuhiro; Hayakawa, Hideaki; Okada, Atsushi; Uchiyama, Takashi; Miyoki, Shinji; Ohashi, Masatake; Kuroda, Kazuaki; Kanda, Nobuyuki; Tatsumi, Daisuke; Tsunesada, Yoshiki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582 (Japan); Department of Physics, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, Osaka 558-8585 (Japan); National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

2008-07-15

280

Image reconstruction and material Z discrimination via cosmic ray muon radiography  

Microsoft Academic Search

Highly penetrating cosmic ray muons shower the Earth at the rate of 10,000m?2min?1 at sea level. In our previous work (Nature 422 (2003) 277; Rev. Sci. Instr. 74(10) (2003) 4294; Cosmic Ray Muon Radiography for Contraband Detection, in: Proceedings of AccApp’03, San Diego, CA, June 2003), we presented a novel muon radiography technique which exploits the multiple Coulomb scattering of

L. J. Schultz; K. N. Borozdin; J. J. Gomez; G. E. Hogan; J. A. McGill; C. L. Morris; W. C. Priedhorsky; A. Saunders; M. E. Teasdale

2004-01-01

281

IHEP (Protvino) 3×3 m2 cosmic ray muon tomograph  

Microsoft Academic Search

Muon tomography, based on the measurement of multiple scattering of cosmic ray muons traversing a volume to be investigated, is an attractive technique for detecting hidden high-Z materials. A cosmic ray muon tomograph with sensitive volume of 3m × 3m × 2.5m has been constructed at IHEP (Protvino) and is under producing first data and results. The description and characteristics

M. Bogolyubskiy; N. Bozhko; A. Borisov; R. Fakhrutdinov; A. Isaev; A. Kozelov; A. Kozhin; I. Plotnikov; V. Senko; N. Shalanda; M. Soldatov; V. Yakimchuk; O. Yushchenko

2011-01-01

282

The Cosmic-Ray Isotope Spectrometer for the Advanced Composition Explorer  

Microsoft Academic Search

The Cosmic-Ray Isotope Spectrometer is designed to cover the highest decade of the Advanced Composition Explorer's energy\\u000a interval, from ?50 to ?500 MeV nucl?1, with isotopic resolution for elements from Z?2 to Z?30. The nuclei detected in this\\u000a energy interval are predominantly cosmic rays originating in our Galaxy. This sample of galactic matter can be used to investigate\\u000a the nucleosynthesis

E. C. Stone; C. M. S. Cohen; W. R. Cook; A. C. Cummings; B. Gauld; B. Kecman; R. A. Leske; R. A. Mewaldt; M. R. Thayer; B. L. Dougherty; R. L. Grumm; B. D. Milliken; R. G. Radocinski; M. E. Wiedenbeck; E. R. Christian; S. Shuman; H. Trexel; T. T. von Rosenvinge; W. R. Binns; D. J. Crary; P. Dowkontt; J. Epstein; P. L. Hink; J. Klarmann; M. Lijowski; M. A. Olevitch

1998-01-01

283

Identifying solar events by the unusual behavior of cosmic rays  

Microsoft Academic Search

It is well known that the Sun occasionally emit bursts of matter and radiation called solar events. The common types of them are solar flares and coronal mass ejections (CMEs). When these solar transients travel in the interplanetary space, some of the Galactic Cosmic Rays are swept away and a sudden decrease in cosmic ray flux is seen by almost

Manjula Jain; M. L. Chauhan; S. K. Shrivastava

2010-01-01

284

Balloon test project: Cosmic Ray Antimatter Calorimeter (CRAC)  

NASA Technical Reports Server (NTRS)

Cosmic ray observations from balloon flights are discussed. The cosmic ray antimatter calorimeter (CRAC) experiment attempts to measure the flux of antimatter in the 200-600 Mev/m energy range and the isotopes of light elements between 600 and 1,000 Mev/m.

Christy, J. C.; Dhenain, G.; Goret, P.; Jorand, J.; Masse, P.; Mestreau, P.; Petrou, N.; Robin, A.

1984-01-01

285

Ultrahigh Energy Cosmic Rays: Old Physics or New Physics.  

National Technical Information Service (NTIS)

We consider the advantages of and the problems associated with hypotheses to explain the origin of ultrahigh energy cosmic rays (UHECR: E greater than 10 EeV) and the 'trans-GZK' cosmic rays (TGZK: E greater than 100 EeV) both through 'old physics' (accel...

F. W. Stecker

2004-01-01

286

Modulation of Cosmic Ray Precipitation Related to Climate  

NASA Technical Reports Server (NTRS)

High energy cosmic rays may influence the formation of clouds, and thus can have an impact on weather and climate. Cosmic rays in the solar wind are incident on the magnetosphere boundary and are then transmitted through the magnetosphere and atmosphere to reach the upper troposphere.

Feynman, J.; Ruzmaikin, A.

1998-01-01

287

The cosmic ray burst on 28 January 1967  

NASA Technical Reports Server (NTRS)

The solar cosmic ray flare which took place on January 28, 1967, is analyzed. Energy responses and the diffusion coefficient are determined. Periodic variations of the cosmic rays with an amplitude of 0.10 to 0.20% and a period of 35 to 40 min are discovered during the decrease phase of the flare.

Chirkov, N. P.; Krymskiy, G. F.; Samsonov, I. S.; Ipatev, V. I.

1975-01-01

288

Real-time cosmic ray monitoring system for space weather  

Microsoft Academic Search

We have developed a real-time system to monitor high-energy cosmic rays for use in space weather forecasting and specification. Neutron monitors and muon detectors are used for our system, making it possible to observe cosmic rays with dual energy range observations. In large solar energetic particle (SEP) events, the ground level enhancement (GLE) can provide the earliest alert for the

T. Kuwabara; J. W. Bieber; J. Clem; P. Evenson; R. Pyle; K. Munakata; S. Yasue; C. Kato; S. Akahane; M. Koyama; Z. Fujii; M. L. Duldig; J. E. Humble; M. R. Silva; N. B. Trivedi; W. D. Gonzalez; N. J. Schuch

2006-01-01

289

Cosmic ray ruggedness of IGBTs for hybrid vehicles  

Microsoft Academic Search

Power semiconductors that are used under high voltage conditions in hybrid vehicles (HVs) are required to have a high destruction tolerance against cosmic rays as well as to meet conventional quality standards. This paper describes an investigation into the failure mechanism for single event burnouts (SEB) induced by cosmic rays in insulated gate bipolar transistors (IGBTs). Device destruction tolerance can

Shuichi Nishida; Tomoyuki Shoji; Toyokazu Ohnishi; Touma Fujikawa; Noboru Nose; Masayasu Ishiko; Kimimori Hamada

2010-01-01

290

Cosmic Ray Ruggedness of Power Semiconductor Devices for Hybrid Vehicles  

Microsoft Academic Search

Power semiconductors that are used under high voltage conditions in hybrid vehicles (HVs) are required to have a high destruction tolerance against cosmic rays as well as to meet conventional quality standards. In this paper, the failure mechanism for single event burnouts (SEB) induced by cosmic rays in insulated gate bipolar transistors (IGBTs) was investigated. Device destruction tolerance can be

Shuichi Nishida; Tomoyuki Shoji; Toyokazu Ohnishi; Touma Fujikawa; Noboru Nose; Masayasu Ishiko; Kimimori Hamada

2010-01-01

291

Very High Energy Cosmic Rays and Their Interactions  

NASA Astrophysics Data System (ADS)

The investigation of high energy cosmic rays and their interactions is a very active field of research. This article summarizes the progress made during the last years as reflected by the contributions to the XIII International Symposium on Very High Energy Cosmic Ray Interactions held in Pylos, Greece.

Engel, Ralph

2006-01-01

292

Cosmic Rays in the Galaxy: Convection or Diffusion.  

National Technical Information Service (NTIS)

The theory of the self-trapping of cosmic rays in our Galaxy shows that cosmic-ray particles stream steadily away from their sources at a speed given by that of hydromagnetic waves. Random diffusion along magnetic field lines is a comparatively negligible...

J. Skilling

1971-01-01

293

Cosmic Ray Sampling of a Clumpy Interstellar Medium  

NASA Astrophysics Data System (ADS)

How cosmic rays sample the multi-phase interstellar medium (ISM) in starburst galaxies has important implications for many science goals, including evaluating the cosmic ray calorimeter model for these systems, predicting their neutrino fluxes, and modeling their winds. Here, we use Monte Carlo simulations to study cosmic ray sampling of a simple, two-phase ISM under conditions similar to those of the prototypical starburst galaxy M82. The assumption that cosmic rays sample the mean density of the ISM in the starburst region is assessed over a multi-dimensional parameter space where we vary the number of molecular clouds, the galactic wind speed, the extent to which the magnetic field is tangled, and the cosmic ray injection mechanism. We evaluate the ratio of the emissivity from pion production in molecular clouds to the emissivity that would be observed if the cosmic rays sampled the mean density, and seek areas of parameter space where this ratio differs significantly from unity. The assumption that cosmic rays sample the mean density holds over much of parameter space; however, this assumption begins to break down for high cloud density, injection close to the clouds, and a very tangled magnetic field. We conclude by evaluating the extent to which our simulated starburst region behaves as a proton calorimeter and constructing the time-dependent spectrum of a burst of cosmic rays.

Boettcher, Erin; Zweibel, Ellen G.; Yoast-Hull, Tova M.; Gallagher, J. S., III

2013-12-01

294

The acceleration of cosmic rays by shock waves  

Microsoft Academic Search

The direct transfer of energy to cosmic rays from supersonic motions of the background medium via shock waves, by means of an efficient first order Fermi mechanism, is considered. The acceleration of cosmic rays by shock waves is most effective in the dilute and hot, 1,000,000-K component of the interstellar medium. There is no limit to the energy that can

W. I. Axford

1981-01-01

295

Cosmic ray particle dosimetry and trajectory tracing. [cosmic ray track analysis for Apollo 17 BIOCORE  

NASA Technical Reports Server (NTRS)

Five pocket mice (Perognathus longimembris) were flown on Apollo XVII, each with a solid-state (plastic) nuclear track detector implanted beneath its scalp. The subscalp detectors were sensitive to HZE cosmic ray particles with a LET greater than or approximately equal to 0.15 million electron volts per micrometer (MeV/micron). A critical aspect of the dosimetry of the experiment involved tracing individual particle trajectories through each mouse head from particle tracks registered in the individual subscalp detectors, thereby establishing a one-to-one correspondence between a trajectory location in the tissue and the presence or absence of a lesion. The other major aspect was the identification of each registered particle. An average of 16 particles with Z greater than or equal to 6 and 2.2 particles with Z greater than or equal to 20 were found per detector. The track density, 29 tracks/sq cm, when adjusted for detection volume, was in agreement with the photographic emulsion data from an area dosimeter located next to the flight package.

Cruty, M. R.; Benton, E. V.; Turnbill, C. E.; Philpott, D. E.

1975-01-01

296

Primary cosmic ray positrons and galactic annihilation radiation  

NASA Technical Reports Server (NTRS)

The observation (Leventhal et al, 1978) of positron annihilation radiation at 0.511 MeV from the direction of the Galactic Center is reexamined, suggesting the possibility of a primary positron component of the cosmic rays. The observed 0.511 MeV emission requires a positron production rate nearly two orders of magnitude greater than the production rate of secondary cosmic ray positrons from pion decay produced in cosmic ray interactions. Possible sources of positrons are reviewed with both supernovae and pulsars appearing to be the more likely candidates. If only about 1% of these positrons were accelerated along with the cosmic ray nucleons and electrons to energies not less than 100 MeV, it is believed that these primary positrons would be comparable in intensity to those secondary positrons resulting from pion decay. Some observational evidence for the existence of primary positrons in the cosmic rays is also discussed.

Lingenfelter, R. E.; Ramaty, R.

1980-01-01

297

The cosmic ray interplanetary radial gradient from 1972 - 1985  

NASA Astrophysics Data System (ADS)

It is now established that the solar modulation of cosmic rays is produced by turbulent magnetic fields propagated outward by the solar wind. Changes in cosmic ray intensity are not simultaneous throughout the modulation region, thus requiring time dependent theories for the cosmic ray modulation. Fundamental to an overall understanding of this observed time dependent cosmic ray modulation is the behavior of the radial intensity gradient with time and heliocentric distance over the course of a solar modulation cycle. The period from 1977 to 1985 when data are available from the cosmic ray telescopes on Pioneer (P) 10, Voyager (V) 1 and 2, and IMP 8 spacecraft is studied. Additional data from P10 and other IMP satellites for 1972 to 1977 can be used to determine the gradient at the minimum in the solar modulation cycle and as a function of heliocentric distance. All of these telescopes have thresholds for protons and helium nuclei of E 60 MeV/nucleon.

Webber, W. R.; Lockwood, J. A.

1985-08-01

298

Terrestrial Effects of High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

On geological timescales, the Earth is likely to be exposed to an increased flux of high energy cosmic rays (HECRs) from astrophysical sources such as nearby supernovae, gamma ray bursts or by galactic shocks. These high-energy particles strike the Earth's atmosphere initiating an extensive air shower. As the air shower propagates deeper, it ionizes the atmosphere by producing charged secondary particles. Increased ionization could lead to changes in atmospheric chemistry, resulting in ozone depletion. This could increase the flux of solar UVB radiation at the surface, which is potentially harmful to living organisms. Increased ionization affects the global electrical circuit can could possibly enhance the low-altitude cloud formation rate. Secondary particles such as muons and thermal neutrons produced as a result of nuclear interactions are able to reach the ground, enhancing the biological radiation dose. The muon flux dominates radiation dose from cosmic rays causing DNA damage and increase in the mutation rates, which can have serious biological implications for terrestrial and sub-terrestrial life. This radiation dose is an important constraint on the habitability of a planet. Using CORSIKA, we perform massive computer simulations and construct lookup tables from 10 GeV - 1 PeV primaries (1 PeV - 0.1 ZeV in progress), which can be used to quantify these effects. These tables are freely available to the community and can be used for other studies, not necessarily relevant to Astrobiology. We use these tables to study the terrestrial implications of galactic shock generated by the infall of our galaxy toward the Virgo cluster. This could be a possible mechanism explaining the observed periodicity in biodiversity in paleobiology databases.

Atri, Dimitra

2011-01-01

299

The cosmic X-ray background. [heao observations  

NASA Technical Reports Server (NTRS)

The cosmic X-ray experiment carried out with the A2 Instrument on HEAO-1 made systematics-free measurements of the extra-galactic X-ray sky and yielded the broadband spectral characteristics for two extreme aspects of this radiation. For the apparently isotropic radiation of cosmological origin that dominates the extragalactic X-ray flux ( 3 keV), the spectrum over the energy band of maximum intensity is remarkably well described by a thermal model with a temperature of a half-billion degrees. At the other extreme, broadband observations of individual extragalactic X-ray sources with HEAO-1 are restricted to objects within the present epoch. While the non-thermal hard spectral components associated with unevolved X-ray emitting active galaxies could account for most of the gamma-ray background, the contribution of such sources to the X-ray background must be relatively small. In contrast, the 'deep-space' sources detected in soft X-rays with the HEAO-2 telescope probably represent a major portion of the extragalactic soft X-ray ( 3 keV) background.

Boldt, E. A.

1980-01-01

300

Cosmic-ray physics with the milagro gamma-ray observatory  

SciTech Connect

The Milagro gamma-ray observatory is a water Cherenkov detector with an energy response between 100 GeV and 100 TeV. While the major scientific goals of Milagro were to detect and study cosmic sources of TeV gamma rays, Milagro has made measurements important to furthering our understanding of the cosmic radiation that pervades our Galaxy. Milagro has made the first measurement of the Galactic diffuse emission in the TeV energy band. In the Cygnus Region we measure a flux {approx}2.7 times that predicted by GALPROP. Milagro has also made measurements of the anisotropy of the arrival directions of the local cosmic radiation. On large scales the measurements made by Milagro agree with those previously reported by the Tibet AS{gamma} array. However, we have also discovered a time dependence to this anisotropy, perhaps due to solar modulation. On smaller scales, {approx}10 degrees, we have detected two regions of excess. These excesses have a spectrum that is inconsistent with the local cosmic-ray spectrum.

Sinnis, Gus [Los Alamos National Laboratory

2008-01-01

301

A Portable Classroom Cosmic Ray Detector  

NASA Astrophysics Data System (ADS)

Normally, one has to work at an accelerator to demonstrate the principles of particle physics. We have developed a portable cosmic ray detector, the Berkeley Lab Detector, that can bring high energy physics experimentation into the classroom. The detector, which is powered by either batteries or AC power, consists of two scintillator paddles with a printed circuit board. The printed circuit board takes the analog signals from the paddles, compares them, and determines whether the pulses arrived at the same time. It has a visual display and a computer output. The output is compatible with commonly found probes in high schools and colleges. A bright high school student can assemble it. Teachers and students have used a working detector on six of the world's continents. These activities have included cross country trips, science projects, and classroom demonstrations. A complete description can be found at the web site: cosmic.lbl.gov. Besides, basic particle physics, the detector can be used to teach statistics and also to provide an opportunity where students have to determine how much data are taken. In this presentation, we will demonstrate the detector and describe some of the projects that teachers and students have completed with it.

Matis, Howard

2012-03-01

302

PREFACE: 23rd European Cosmic Ray Symposium (and 32nd Russian Cosmic Ray Conference)  

NASA Astrophysics Data System (ADS)

The 23rd European Cosmic Ray Symposium (ECRS) took place in Moscow at the Lomonosov Moscow State University (3-7 July 2012), and was excellently organized by the Skobeltsyn Institute of Nuclear Physics of the Lomonosov Moscow State University, with the help of the Russian Academy of Sciences and the Council on the Complex Problem of Cosmic Rays of the Russian Academy of Sciences. The first symposia were held in 1968 in Lodz, Poland (high energy, extensive air showers and astrophysical aspects) and in Bern (solar and heliospheric phenomena) and the two 'strands' joined together in 1976 with the meeting in Leeds. Since then the symposia, which have been very successful, have covered all the major topics with some emphasis on European collaborations and on meeting the demands of young scientists. Initially, a driving force was the need to overcome the divisions caused by the 'Cold War' but the symposia continued even when that threat ceased and they have shown no sign of having outlived their usefulness. 2012 has been an important year in the history of cosmic ray studies, in that it marked the centenary of the discovery of enigmatic particles in the perilous balloon ascents of Victor Hess. A number of conferences have taken place in Western Europe during the year, but this one took place in Moscow as a tribute to the successful efforts of many former USSR and other Eastern European scientists in discovering the secrets of the subject, often under very difficult conditions. The symposium covers a wide range of scientific issues divided into the following topics: PCR-IPrimary cosmic rays I (E < 1015 eV) PCR-IIPrimary cosmic rays II (E > 1015 eV) MNCosmic ray muons and neutrinos GAGeV and TeV gamma astronomy SHEnergetic particles in the heliosphere (solar and anomalous CRs and GCR modulation) GEOCosmic rays and geophysics (energetic particles in the atmosphere and magnetosphere of the Earth) On a personal note, as I step down as co-founder and chairman of the International Advisory Committee, I should like to thank those very many colleagues and friends with whom I have had the pleasure of working over the past 45 years. These thanks are extended to the present organizers. The organizers are very grateful to the Russian Foundation of Basic Research and to the Dynasty non-profit foundation for financial support. Arnold Wolfendale

Erlykin, A. D.; Kokoulin, R. P.; Lidvansky, A. S.; Meroshnichenko, L. I.; Panasyuk, M. I.; Panov, A. D.; Wolfendale, A. W.

2013-02-01

303

Galactic cosmic rays in a dynamic heliosphere  

NASA Astrophysics Data System (ADS)

The relation between the dynamics of the heliosphere, also its shape and geometry, and solar activity has become increasingly important. The global features of the heliosphere influence what happens inside its boundaries on a variety of time-scales. Galactic cosmic rays (GCRs) serve as excellent probes for this purpose, conveying vital information on global and local changes in the way that they respond to them. By observing GCRs, and other charged particles, over a wide range of energies on various spacecraft and satellites and on Earth, a better understanding is gained about these heliospheric features, the basics of particle transport and modulation, and various heliospace phenomena, including space weather and space climate. Significant progress is made with numerical modeling in this field, stimulated by in situ observations in the outer heliosphere by the two Voyager spacecraft and in the inner heliosphere by ULYSSES, PAMELA, STEREO and other space missions.

Potgieter, Marius

2012-07-01

304

Transport and acceleration of anomalous cosmic rays  

NASA Astrophysics Data System (ADS)

Anomalous cosmic rays are produced from interstellar pickup ions by heliospheric plasma processes. The solar wind termination shock was believed to be the source of these high-energy ions before the Voyagers' shock encounter. Because ACR spectra were observed to be modulated at the shock, several different acceleration cites and mechanisms were proposed. These included termination shock locations not visited by the Voyagers, the inner helioshgeath, and regions near the heliopause. I will review and compare the current generation of ACR transport models, including an update on the Huntsville model. A need to accommodate a physically realistic geometry of the termination shock and heliosheath for ACR modeling is emphasized. I also discuss recent ACR flux decreases as a sign of Voyager's proximity to the heliopause.

Florinski, Vladimir; Senanayake, Udara

2012-07-01

305

The beginning of cosmic ray astrophysics  

NASA Astrophysics Data System (ADS)

A short history of the beginning of cosmic ray (CR) astrophysics is considered: from the hypothesis on CR origin as a result of Supernova explosions in the Metagalaxy, to a model of solar origin of CR, galactic origin based on the stochastic mechanism of charged particle acceleration in interstellar space, to extragalactic and hierarchical models of CR origin, as well as galactic CR origin taking into account radio-astronomical data. We consider also the first balloon results on the chemical contents of primary CR (especially of the contents Li, Be, B), important for any model of CR origin. Investigations of the injection problem, CR drift and diffusion acceleration by shock waves, and CR generation in Supernova remnants were also important steps in the beginning of CR astrophysics.

Dorman, L. I.; Dorman, I. V.

2014-05-01

306

Cosmic Ray Variability and Galactic Dynamics  

NASA Astrophysics Data System (ADS)

The spectral analysis of fluctuations of biodiversity (Rohde & Muller, 2005) and the subsequent re-analysis of the diversity record, species origination and extinction rates, gene duplication, etc (Melott & Liebermann, 2007) indicate the presence of a 62$\\pm$3My cyclicity, for the last 500My. Medvedev & Melott (2006) proposed that the cyclicity may be related to the periodicity of the Solar motion with respect to the Galactic plane, which exhibits a 63My oscillation, and the inhomogeneous distribution of Cosmic Rays (CR) throughout the Milky Way, which may affect the biosphere by changing mutation rate, climate, food chain, etc. Here we present a model of CR propagation in the Galactic magnetic fields, in the presence of both the mean field gradient and the strong MHD turbulence in the interstellar medium. We explore the "magnetic shielding effect" as a function of CR energy and composition and estimate the resultant flux of mutagenic secondary muons at the Earth surface.

Medvedev, Mikhail

2007-05-01

307

A Cosmic Ray Telescope For Educational Purposes  

NASA Astrophysics Data System (ADS)

Cosmic ray detectors are widely used, for educational purposes, in order to motivate students to the physics of elementary particles and astrophysics. Using a ``telescope'' of scintillation counters, the directional characteristics, diurnal variation, correlation with solar activity, can be determined, and conclusions about the composition, origin and interaction of elementary particles with the magnetic field of earth can be inferred. A telescope was built from two rectangular scintillator panels with dimensions: 91.6×1.9×3.7 cm3. The scintillators are placed on top of each other, separated by a fixed distance of 34.6 cm. They are supported by a wooden frame which can be rotated around a horizontal axis. Direction is determined by the coincidence of the signals of the two PMTs. Standard NIM modules are used for readout. This device is to be used in the undergraduate nuclear and particle physics laboratory. The design and construction of the telescope as well as some preliminary results are presented.

Voulgaris, G.; Kazanas, S.; Chamilothoris, I.

2010-01-01

308

Stars and Cosmic Rays Observed from Mars  

NASA Technical Reports Server (NTRS)

In this five-minute exposure taken from the surface of Mars by NASA's Spirit rover, stars appear as streaks due to the rotation of the planet, and instantaneous cosmic-ray hits appear as points of light.

Spirit took the image with its panoramic camera on March 11, 2004, after waking up during the martian night for a communication session with NASA's Mars Global Surveyor orbiter. Other exposures were also taken. The images tested the capabilities of the rover for night-sky observations. Scientists will use the results to aid planning for possible future astronomical observations from Mars.

The difference in Mars' rotation, compared to Earth's, gives the star trails in this image a different orientation than they would have in a comparable exposure taken from Earth.

2004-01-01

309

Statistical reconstruction for cosmic ray muon tomography.  

PubMed

Highly penetrating cosmic ray muons constantly shower the earth at a rate of about 1 muon per cm2 per minute. We have developed a technique which exploits the multiple Coulomb scattering of these particles to perform nondestructive inspection without the use of artificial radiation. In prior work [1]-[3], we have described heuristic methods for processing muon data to create reconstructed images. In this paper, we present a maximum likelihood/expectation maximization tomographic reconstruction algorithm designed for the technique. This algorithm borrows much from techniques used in medical imaging, particularly emission tomography, but the statistics of muon scattering dictates differences. We describe the statistical model for multiple scattering, derive the reconstruction algorithm, and present simulated examples. We also propose methods to improve the robustness of the algorithm to experimental errors and events departing from the statistical model. PMID:17688203

Schultz, Larry J; Blanpied, Gary S; Borozdin, Konstantin N; Fraser, Andrew M; Hengartner, Nicolas W; Klimenko, Alexei V; Morris, Christopher L; Orum, Chris; Sossong, Michael J

2007-08-01

310

TIROS-N Cosmic Ray study  

NASA Technical Reports Server (NTRS)

An experimental and analytical study was performed on the impact of galactic cosmic rays on the TIROS-N satellite memory in orbit. Comparisons were made of systems equipped with the Harris HMI-6508 1 x 1024 CMOS/bulk RAM and the RCA CDP-1821 1 x 1024 bit CMOS/SOS RAM. Based upon the experimental results, estimated bit error rates were determined. These were at least 8.0 bit errors/day for a 300 kilobit memory with the HMI-6508 and .014 bit errors/day with the CDF-1821. It was also estimated that the HMI-6508 latchup rate in orbit is at least two orders of magnitude less than the bit error rates; the CDP-1821 will not latchup.

Blandford, J. T., Jr.; Pickel, J. C.

1980-01-01

311

Cosmic ray drift, shock wave acceleration and the anomalous component of cosmic rays  

NASA Technical Reports Server (NTRS)

A model of the anomalous component of the quiet-time cosmic ray flux is presented in which ex-interstellar neutral particles are accelerated continuously in the polar regions of the solar-wind termination shock, and then drift into the equatorial regions of the inner heliosphere. The observed solar-cycle variations, radial gradient, and apparent latitude gradient of the anomalous component are a natural consequence of this model.

Pesses, M. E.; Jokipii, J. R.; Eichler, D.

1981-01-01

312

Low-energy cosmic ray protons from nuclear interactions of cosmic rays with the interstellar medium.  

NASA Technical Reports Server (NTRS)

The intensity of low-energy (less than 100 MeV) protons from nuclear interactions of higher-energy (above 100 MeV) cosmic rays with the interstellar medium is calculated. The resultant intensity in the 10- to 100-MeV range is larger by a factor of 3-5 than the observed proton intensity near earth. The calculated intensity from nuclear interactions constitutes a lower limit on the actual proton intensity in interstellar space.

Wang, H. T.

1973-01-01

313

Cosmic ray drift, shock wave acceleration, and the anomalous component of cosmic rays  

Microsoft Academic Search

A model of the anomalous component of the quiet-time cosmic ray flux is presented in which ex--interstellar neutral particles are accelerated continuously in the polar regions of the solar-wind termination shock and then drift into the equatorial regions of the inner heliosphere. The observed solar-cycle variations, radial gradient, and apparent latitude gradient of the anomalous component are a natural consequence

M. E. Pesses; J. R. Jokipii; D. Eichler

1981-01-01

314

Cosmic Ray Statistics using LabVIEW  

NSDL National Science Digital Library

Counting statistics of cosmic rays is explored using a LabVIEW based computer program on a computer connected to a National Instruments data acquisition unit. The program collects the interval times between successive coincident pulses from a stack of plastic scintillator detectors. Analysis of the data set allows students to see the distribution of N-pulse intervals for various values of N; this is the Erlang distribution. With N = 1, the Erlang distribution is exponential with a characteristic time equal to mean count interval t. When N is increased, the distribution becomes peaked at Nt with a fractional width proportional to 1/?N. This is an instance of the central limit theorem. Students may also examine the data set according to the distribution of numbers of pulses recorded for a series of fixed-length intervals, which for random pulses follows the Poisson distribution. Again, as the length of the interval increases, the distribution conforms to the central limit theorem: it becomes normal with a well-defined mean and width, both related to mean and width of the underlying distribution. The software also allows students to simulate pulse-intervals that follow a uniform distribution (e.g., any real number between 0 and 1 has equal probability) or a Gaussian one. In these cases, one can see that the counts per fixed interval length do not follow the Poisson distribution, although all types become normal at longer intervals or greater numbers of pulses per interval length. This serves to drive home the point that cosmic ray counts are truly a Poisson process and also to illustrate the significant power of the central limit theoremâ that regardless of the underlying probability distribution function, when N becomes large the distribution becomes normal with a well-defined mean and width. Presented at the 2013 AAPT Summer Meeting in Portland, Oregon. W36: Advanced Labs Workshop

Pengra, David B.

2013-10-02

315

Evidence for the Superbubble Origin of Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

Measurements of the isotopic and elemental abundances of galactic cosmic rays from the Cosmic Ray Isotope Spectrometer (CRIS) aboard the NASA-ACE spacecraft, and elemental abundances from the balloon-borne Trans-Iron Galactic Element Recorder (TIGER) provide strong evidence that a large fraction of galactic cosmic rays originate and are accelerated in associations of massive stars (OB associations) and their associated superbubbles. Neon and iron isotopic abundances point to a superbubble origin in which the galactic cosmic rays (GCRs) come from material that is roughly a 20%-80% mix of OB association material and ordinary interstellar medium material (ISM). This assumption that GCRs come from such a mix instead of ordinary ISM results in greatly improved ordering of volatile and refractory GCR elemental abundances when plotted versus atomic mass. This strengthens the OB association-superbubble connection with cosmic ray origin. More recently, the LAT instrument aboard the Fermi spacecraft has identified distributed emission of gamma-rays from a "cocoon" identified with the Cygnus-X superbubble, indicating the acceleration of cosmic rays in the superbubble. These measurements and the implications for the OB-association/superbubble origin of galactic cosmic rays will be discussed. Principal funding for this research was from NASA under grants NNG05WC04G and NAG5-12929.

Binns, W.

2012-12-01

316

Plasma Effects on Extragalactic Ultra-high-energy Cosmic Ray Hadron Beams in Cosmic Voids  

NASA Astrophysics Data System (ADS)

The linear instability of an ultrarelativistic hadron beam (? b ? 106) in the unmagnetized intergalactic medium (IGM) is investigated with respect to the excitation of collective electrostatic and aperiodic electromagnetic fluctuations. This analysis is important for the propagation of extragalactic ultrarelativistic cosmic rays (E > 1015 eV) from their distant sources to Earth. We calculate minimum instability growth times that are orders of magnitude shorter than the cosmic ray propagation time in the IGM. Due to nonlinear effects, especially the modulation instability, the cosmic ray beam stabilizes and can propagate with nearly no energy loss through the IGM.

Krakau, S.; Schlickeiser, R.

2014-07-01

317

X-ray Production By Cosmic Muons  

SciTech Connect

Muons have a small cross section for interactions and high energy, so they are very penetrating and give the significant contribution to the gamma spectra of Ge detectors, even in deep underground laboratories. One of the muon interaction effects with material is X-rays production. Having in mind that gold is often used as a detectors component, in this paper the production of X-rays in gold sample is analyzed by using an coincidence system based on plastic scintillation detector and Ge detector. The Au disc-shaped sample with mass of 40.6 g, radius 3.34 cm and 0.06 cm thickness was inside 12 cm thick lead shield of extended range HPGe detector. The plastic detector of 0.5 x 0.5 x 0.05 m dimensions was placed above the lead shield at the distance of 32 cm from detector endcap. The producing rate of K{alpha} rays per Au mass unit from coincidence gamma spectrum is determined as R {approx_equal}7.1 x 10-4 g-1s-1. Taking in account the measured muon flux of {phi}=54 s-1m-2, the muon cross section {sigma}K{alpha}{approx_equal} 43 Barn, for Au K{alpha} X-rays production is calculated. Also, the cross sections of X-ray production by cosmic muons in lead and tungsten are measured. Unexpectedly, the results obtained did not reveal Z dependence in the Z= 74-82 region.

Mrdja, D.; Bikit, I.; Veskovic, M.; Forkapic, S. [Department of Physics, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovica 4, 21 000 Novi Sad (Serbia); Anicin, I. [Faculty of Physics, University of Belgrade, Studentski trg 12-16, 11 000 Belgrade (Serbia)

2007-04-23

318

A search for microwave emission from cosmic ray air showers  

NASA Astrophysics Data System (ADS)

At the highest energies, the sources of cosmic rays should be among the most powerful extragalactic accelerators. Large observatories have revealed a flux suppression above a few 1019 eV, similar to the expected effect of the interaction of ultrahigh energy cosmic rays (UHECR) with the cosmic microwave background. The Pierre Auger Observatory has measured the largest sample of cosmic ray induced extensive air showers (EAS) at the highest energies leading to a precise measurement of the energy spectrum, hints of spatial anisotropy, and a surprising change in the chemical composition at the highest energies. To answer the question of the origin of UHECRs a larger sample of high quality data will be required to reach a statistically significant result. One of the possible techniques suggested to achieve this much larger data sample, in a cost effective way, is ultra-wide field of view microwave telescopes which would operate in an analogous way to the already successful fluorescence detection (FD) technique. Detecting EAS in microwaves could be done with 100% duty cycle and essentially no atmospheric effects. This presents many advantages over the FD which has a 10% duty cycle and requires extensive atmospheric monitoring for calibration. We have pursued both prototype detector designs and improved laboratory measurements, the results of which are reported herein, and published in (Alvarez-Muniz et al., 2013; Alvarez-Muniz et al., 2012a; Williams et al., 2013; Alvarez-Muniz et al., 2013). The Microwave Detection of Air Showers (MIDAS) experiment is the first ultra-wide field of view imaging telescope deployed to detect isotropic microwave emission from EAS. With 61 days of livetime data operating on the University of Chicago campus we were able to set new limits on isotropic microwave emission from extensive air showers. The new limits rule out current laboratory air plasma measurements (Gorham et al., 2008) by more than five sigma. The MIDAS experiment continues to take data installed in Argentina, operating in coincidence with the Pierre Auger Observatory. Using the first 70 days of livetime data combined with a sample of EAS events from the Auger surface detector we are able to set a preliminary limit which is even more stringent than that set with the Chicago data set. Test beam efforts performed at Argonne National Lab, The Microwave Air Yield Beam Experiment (MAYBE), have successfully measured a microwave signal which exhibits linear scaling with energy deposit in a frequency range of 1 GHz to 15 GHz. This measurement has produced strong upper limits on the isotropic emission of microwaves from air plasmas.

Williams, Christopher Lee

319

Cosmic rays IX. Interactions and transport of cosmic rays in the Galaxy  

NASA Astrophysics Data System (ADS)

We propose that cosmic rays interact mostly near their sources of origin. To be specific, we differentiate the various supernovae by their mass of the progenitor star along the zero age main sequence. Stars between about 8 and 15 solar masses explode into the interstellar medium, and accelerate cosmic rays, as discussed by many for some time. From about 15 to 25 solar masses stars explode into their own stellar wind; this wind has built up a thin shell of both wind material and interstellar medium material in the red and blue giant phases preceding the supernova event. The shock accelerating cosmic ray particles races through that wind, gets loaded up with energetic particles, interacts while it goes, and finally smashes into the shell. While the shock goes out, it snowplows the entire wind into the pre-existing shell to form a composite shell. We propose that for the mass range 15 to 25 solar masses this composite shell is immediately broken up so that the time scale for interaction is caused by the breakup and so is convective. We note that the wind material for this range of zero age masses is a approximately half helium, and half hydrogen. The interactions in the composite wind-shell and the immediate environment produce positrons, gamma emission, but only few secondary nuclei, because for this mass range the enrichment in heavier elements is still minor. The energy spectrum of the gamma emission and the positrons produced corresponds then to the source spectrum. In contrast, from about 25 solar masses and up the wind is strongly enriched in heavy elements, and the wind shell is massive, comprising most of the initial zero age star's mass, as well as a good part of the local interstellar medium. We propose that for the interaction of the cosmic ray particles carried out by the shock in the snow-plow through the wind to the shell the interaction is diffusive, and calculate the diffusion coefficient. This leads to a leakage time energy dependence of E-5/9 in the relativistic limit. This then gives an energy dependence of secondary nuclei, that matches the observations. There is a second component of positrons, and also gamma emission, but then at moderate energies all with the steeper energy dependence; spatial and velocity constraints give both a lower as well as an upper rigidity limit to the diffusion approximation. One important element in such a picture is the steady mixing of newly enriched material throughout the star before the explosion, induced by Voigt-Eddington circulation caused by rotation. The mixed material is then ejected through the wind, which at the end provides the source material for cosmic ray injection. This means that by the time the nuclei are subject to acceleration, they should have decayed already to final states, an effect which may be measureable in cosmic ray isotope ratios. Therefore, considering the history of the travel of cosmic rays through the normal interstellar medium, we can readily explain the ratio of secondaries to primaries, and at the same time use a spectrum of turbulence in the interstellar medium, a Kolmogorov spectrum, which is consistent with all other observational evidence. The escape time from the Galaxy is then proportional to E-1/3 in the relativistic range of particle energies. Translating this result into the language common in the literature, this means that interaction path as measured in gm/cm2 and escape time can not be used synonymously.

Biermann, P. L.; Langer, N.; Seo, Eun-Suk; Stanev, T.

2001-04-01

320

Change in cosmic-ray spectrum through the production of electron-positron pairs (analytical approach)  

SciTech Connect

We consider the change in primordial cosmic-ray spectrum through the production of electron-positron pairs in collisions with cosmic microwave background radiation photons. We suggest using these results to estimate the distances to cosmic-ray sources.

Vlasov, V. P., E-mail: vlasov@nfi.kiae.ru; Trubnikov, B. A., E-mail: batrub@nfi.kiae.r [Russian Research Center Kurchatov Institute (Russian Federation)

2009-12-15

321

The HiSCORE concept for gamma-ray and cosmic-ray astrophysics beyond 10 TeV  

NASA Astrophysics Data System (ADS)

Air-shower measurements in the primary energy range beyond 10 TeV can be used to address important questions of astroparticle and particle physics. The most prominent among these questions are the search for the origin of charged Galactic cosmic rays and the so-far little understood transition from Galactic to extra-galactic cosmic rays. A very promising avenue towards answering these fundamental questions is the construction of an air-shower detector with sufficient sensitivity for gamma-rays to identify the accelerators and large exposure to achieve accurate spectroscopy of local cosmic rays. With the new ground-based large-area (up to 100 km2) wide-angle (?˜ 0.6-0.85 sr) air-shower detector concept HiSCORE (Hundred?i Square-km Cosmic ORigin Explorer), we aim at exploring the cosmic ray and gamma-ray sky (accelerator-sky) in the energy range from few 10 s of TeV to 1 EeV using the non-imaging air-Cherenkov detection technique. The full detector simulation is presented here. The resulting sensitivity of a HiSCORE-type detector to gamma-rays will extend the energy range so far accessed by other experiments beyond energies of 50-100 TeV, thereby opening up the ultra high energy gamma-ray (UHE gamma-rays, E > 10 TeV) observation window.

Tluczykont, Martin; Hampf, Daniel; Horns, Dieter; Spitschan, Dominik; Kuzmichev, Leonid; Prosin, Vasily; Spiering, Christian; Wischnewski, Ralf

2014-04-01

322

The survival of heavy nuclei in cosmic ray source environments  

NASA Technical Reports Server (NTRS)

The results are discussed that were obtained from the Goddard balloon spectrometer experiment to study the composition and energy distribution of high energy cosmic rays. The significant findings indicate that: (1) On a total energy scale, protons constitute only a minor proportion of the cosmic rays. They account for only 20 percent; the rest of the cosmic rays are complex nuclei. (2) All the nuclei have the same power low spectrum in total energy and so the composition appears to be independent of energy.

Balasubrahmanyan, V. K.

1972-01-01

323

Effect of cosmic ray on global high cloud from MODIS  

NASA Astrophysics Data System (ADS)

The Earth's climate is affected by not only internal forcings but also external forcings related with solar activities. The energetic particles called "cosmic rays" from outer space have been considered as a potentially important external climate forcing since the first report by Svensemark and Friis-Christensen (1997) which showed a significant correlation between cloudiness and cosmic ray. This correlation is a basis of a couple of hypotheses in microphysical processes: ion-aerosol clear-air mechanism and ion-aerosol near-cloud mechanism. These mechanisms have been either supported or objected by many successive studies, most of which correlated long-term trends of cloud and cosmic ray. However, it is most likely that such methodology is not suitable to find actual connection, because long-term trends of clouds may invite affection by many factors other than cosmic ray. It is therefore necessary to find the relation at shorter time scale, since cosmic ray affect the process of cloud formation in a moment. Here we show spatial distributions of correlation between global high cloud fraction data from MODIS and cosmic ray of neutron monitor data from McMurdo, Antarctic. We removed 3-month running means from the original data in order to get high frequency fluctuations. As results, positive correlations are dominant in the spatial distribution, especially over lands on the northern hemisphere and oceans on the Southern hemisphere. On the other hand, negative correlations exist over limited area including the Indian Ocean. According to the cross-correlation (with time lags), the areas with positive correlation is widely distributed at zero lag. At ±1 month lags, the signs of correlations become the opposite of that at zero lag. Furthermore, the correlation between relative high cloud amount to total cloud and cosmic ray shows similar distribution to the correlation between absolute high cloud amount and cosmic ray, implying stronger high cloud response to cosmic ray than low and middle clouds. Considering the correlations with dependence on regions, a physical cloud process regarding to cosmic ray may not be universal perhaps due to anonymous factors affecting the cloud amount. However, our synthetic conclusion is that the amount of global high cloud increases with increased cosmic ray. This implies that infrared warming effect due to increased high cloud may be intensified when more cosmic ray comes in.

Kim, H.-S.; Choi, Y.-S.

2012-04-01

324

The role of cosmic rays in the protostellar disc formation  

NASA Astrophysics Data System (ADS)

Cosmic rays represent the main actors in regulating the chemical evolution and in setting the ambipolar diffusion time of a molecular cloud. We summarise the processes causing the energy degradation of cosmic rays due to their interaction with molecular hydrogen, also focusing on the magnetic effects that influence their propagation. Making use of magnetic field configurations generated by numerical simulations, we show that the concentration and the wrapping of the field lines in the collapse region lead up to a drop of the cosmic-ray ionisation rate, and consequently of the ionisation fraction, helping to decouple the gas from the magnetic field.

Padovani, M.; Hennebelle, P.; Galli, D.

2013-11-01

325

Satellite measurements of the isotopic composition of galactic cosmic rays  

NASA Technical Reports Server (NTRS)

The individual isotopes of galactic cosmic ray Ne, Mg, and Si at 100 MeV/nucleon were clearly resolved with an rms mass resolution of 0.20 amu. The results suggest the cosmic ray source is enriched in Ne-22, Mg-25, and Mg-26 when compared to the solar system. The ratio of (Mg-25)+(Mg-26) to Mg-24, which is approximately 0.49 compared to the solar system value of 0.27, suggest that the cosmic ray source and solar system material were synthesized under different conditions.

Mewaldt, R. A.; Spalding, J. D.; Stone, E. C.; Vogt, R. E.

1979-01-01

326

Gamma-Ray Burst Detection with Icecube  

NASA Astrophysics Data System (ADS)

With their narrow emission window gamma-ray bursts (GRBs) are among the most promising objects for the first identification of high-energy cosmic neutrinos. If a considerable fraction of the ultra-high energy cosmic rays is indeed produced in GRBs, IceCube, which is now more than half-way completed, should be able to detect the associated neutrinos in the next few years. Furthermore, optical follow-up observations of neutrino multiplets will enhance IceCube's sensitivity to choked GRBs which do not produce a gamma-ray signal.

Kappes, Alexander

327

A cosmic ray cocoon along the X-ray jet of M87?  

NASA Astrophysics Data System (ADS)

Relativistic jets propagating through an ambient medium must produce some observational effects along their side boundaries because of interactions across the large velocity gradient. One possible effect of such an interaction would be a sheared magnetic field structure at the jet boundaries, leading to a characteristic radio polarization pattern. As proposed by Ostrowski, another effect can come from the generation of a high-energy cosmic ray component at the boundary, producing dynamic effects on the medium surrounding the jet and forming a cocoon dominated by cosmic rays with a decreased thermal gas emissivity. We selected this process for our first attempt to look for the effects of this type of interaction. We analysed the Chandra X-ray data for the radio galaxy M87 in order to verify if the expected regions of diminished emissivity may be present near the spectacular X-ray jet in this source. The detailed analysis of the data, merged from 42 separate observations, shows signatures of lower emissivity surrounding the jet. In particular we detect an intensity dip along the part of the jet, which would be approximately 1.5 × 0.15 kpc2 in size, if situated along the jet which is inclined towards us. Due to a highly non-uniform X-ray background in the central region, we are not able to claim the discovery of a cosmic ray cocoon around the M87 jet: we only have demonstrated that the data show morphological structures which could be accounted for if a cosmic ray cocoon exists.

Dainotti, M. G.; Ostrowski, M.; Harris, D.; Siemiginowska, A.; Siejkowski, H.

2012-10-01

328

Cosmic Ray Energetics And Mass: First flight for 42 days  

Microsoft Academic Search

The Cosmic Ray Energetics And Mass (CREAM) balloon-borne experiment had its first flight for nearly 42 days in Antarctica from Dec 15, 2004 to Jan 26, 2005. It made three circumnavigations around the South Pole, which broke both the duration and distance records for a long-duration balloon flight. CREAM was designed to measure the energy spectra and composition of cosmic

Young Soo Yoon

2005-01-01

329

Study of cosmic ray motion in cosmic space near the earth  

NASA Technical Reports Server (NTRS)

Data are presented on experimental installations developed in the cosmic ray variations laboratory in Kazgu (Alma-Ata). Various experiments on modelling the interaction of plasma with the geomagnetic field as well as the plasma distribution in quiet and disturbed fields are described. The characteristics of the meson supertelescope using scintillators (effective area, 10 sq m) for vertical alignments designed to study microvariations of the cosmic rays and their interrelation with magnetospheric fluctuations and the study of solar wind parameters are given.

Budilov, V. K.; Ivanov, V. I.; Kozak, L. V.; Mirkin, L. A.; Tsukerman, I. G.

1975-01-01

330

Exploring Cosmic X-ray Source Polarization  

NASA Technical Reports Server (NTRS)

Cosmic X-ray sources are expected to be polarized, either because of their asymmetry and the role of scattering in their emission or the role of magnetic fields. Polarization at other wavelengths has been useful. X-ray polarization will provide a new handle on black hole parameters, in particular the spin, on accretion flows and outflows, on neutron star spin orientations and emission mechanisms, on the quantum mechanical effects of super-strong magnetic fields of magnetars, and on the structure of supernovae shocks. The proposed Gravity and Extreme Magnetism SMEX (GEMS) will use high efficiency polarimeters behind thin foil mirrors. The statistical sensitivity and control of systematics will allow measurement of polarization fractions as small as 1% from many galactic and extragalactic sources. Targets which should be polarized at the level that GEMS can easily measure include stellar black holes, Seyfert galaxies and quasars, blazars, rotation-powered and accretion-powered pulsars, magnetars, shell supernova remnants and pulsar wind nebulae. The polarimeters are Time Projection Chambers that allow reconstruction of images of photoelectron tracks for 2-10 keV Xrays. They can be deep without sacrificing modulation. These polarimeters do not image the sky, but the telescope point spread function and detector collimation allow structure to be resolved at the 10 arcmin level. Rotation of the spacecraft is not needed for the signal measurement in the Time Projection Chambers, but provides for measurement and correction of systematic errors. It also allows a small Bragg reflection soft X-ray experiment to be included that can be used for isolated neutron stars and blazars.

Swank, Jean Hebb; Jahodal, K.; Kallman, T. R.; Kaaret, P.

2008-01-01

331

Cosmic ray streaming in clusters of galaxies  

NASA Astrophysics Data System (ADS)

The observed bimodality in radio luminosity in galaxy clusters is puzzling: cosmic rays (CRs) accelerated by structure formation shocks are expected to indiscriminately produce bright radio haloes in every cluster. We investigate the possibility that CR streaming in the intracluster medium (ICM) can `switch off' hadronically induced radio and gamma-ray emission. For self-confined CRs, this depends on the source of magnetohydrodynamic wave damping: if only non-linear Landau damping operates, then CRs stream on the slow Alfvénic time-scale, but if turbulent wave damping operates, super-Alfvénic streaming is possible. As turbulence increases, it promotes outward streaming more than it enables inward turbulent advection. Curiously, the CR flux is independent of ?f (as long as it is non-zero) and depends only on plasma parameters; this enables radio haloes with flat inferred CR profiles to turn off. We perform 1D time-dependent calculations of a radio mini-halo (Perseus) and giant radio halo (Coma) and find that both diminish in radio luminosity by an order of magnitude in several hundred Myr, given plausible estimates for the magnetic field in the outskirts of the cluster. Due to the energy dependence of CR streaming, spectral curvature develops, and radio haloes turn off more slowly at low frequencies - properties consistent with observations. Similarly, CR streaming rapidly turns off gamma-ray emission at the high energies probed by Cherenkov telescopes, but not at the low energies probed by Fermi. CR mediated wave heating of the ICM is unaffected, as it is dominated by ˜GeV CRs which stream Alfvénically.

Wiener, Joshua; Oh, S. Peng; Guo, Fulai

2013-09-01

332

Intergalactic Magnetic Fields, and Some Connections with Cosmic Rays  

NASA Astrophysics Data System (ADS)

An overview is presented of the methods of probing for the geometry, and strength of intergalactic magnetic fields. Recent results are briefly surveyed for galaxy halos, galaxy clusters, and the intergalactic medium on various scales, and some rele vant physical processes and radiation processes are mentioned, as well as the “coupling” between intergalactic magnetic fields and cosmic rays. The general trend of recent results indicates that, wherever we detect intergalactic hot gas and galaxies, we also find magnetic fields at levels of ˜ 10-7 G, or higher. The hitherto undetected, weaker fields in the ratified i.g.m. and in large intergalactic voids could be probed by both Faraday rotation, and possibly using very energetic CR nuclei (> 1020eV), and/or transient extragalactic ? ray bursts.

Kronberg, Philipp P.

1996-01-01

333

Galactic cosmic ray variations at the moon  

NASA Astrophysics Data System (ADS)

Galactic Cosmic Rays (GCR) are the predominant source of highly energetic particles in the inner heliosphere during solar quiet times. These particles are fully ionized atoms that are accelerated to near-relativistic speeds during events of extreme energy release throughout the Milky Way Galaxy and beyond. Some GCR particles eventually find their way to the outer edges of the heliosphere and a portion of those are able to propagate to 1 AU. GCR have sufficient energy to ionize atoms and molecules in the matter that they impact, causing radiation damage to both robotic and biologic materials. Understanding the flux and spectrum of GCR is of great importance to future robotic and human explorers venturing beyond low-Earth orbit. In this dissertation, we use the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument along with modeling efforts to study a variety of phenomena that can influence the energetic particle flux in the near-Moon environment, including Interplanetary Coronal Mass Ejections (ICMEs), Corotating Interaction Regions (CIRs) and the Earth's magnetotail. As part of this study, the CRaTER instrument and its calibration are discussed in detail. A new model is developed to better predict the transit times of Interplanetary Coronal Mass Ejections and the associated drops in GCR flux called Forbush decreases. This model could provide a more accurate estimate of an ICME's arrival time within hours of ejection from the Sun. An important model discrepancy is resolved by using the CRaTER instrument to measure GCR while the Moon is in the Earth's magnetotail. Previous studies that predicted shielding of GCR by the magnetotail are disproven; we find no evidence for a drop in GCR, intensity as a result of passage through the magnetotail. We use the CRaTER instrument to investigate step-like durable decreases in GCR flux with time. We find that these decreases occurred when CIRs convected past the observing spacecraft shortly after solar minimum, presumably caused by the more effective shielding provided by the outward propagating magnetic structures. A change in the proton linear energy transfer spectrum is observed in conjunction with the GCR flux decrease.

Case, Anthony W.

2011-05-01

334

Optimal filters for detecting cosmic bubble collisions  

NASA Astrophysics Data System (ADS)

A number of well-motivated extensions of the ?CDM concordance cosmological model postulate the existence of a population of sources embedded in the cosmic microwave background. One such example is the signature of cosmic bubble collisions which arise in models of eternal inflation. The most unambiguous way to test these scenarios is to evaluate the full posterior probability distribution of the global parameters defining the theory; however, a direct evaluation is computationally impractical on large datasets, such as those obtained by the Wilkinson Microwave Anisotropy Probe (WMAP) and Planck. A method to approximate the full posterior has been developed recently, which requires as an input a set of candidate sources which are most likely to give the largest contribution to the likelihood. In this article, we present an improved algorithm for detecting candidate sources using optimal filters, and apply it to detect candidate bubble collision signatures in WMAP 7-year observations. We show both theoretically and through simulations that this algorithm provides an enhancement in sensitivity over previous methods by a factor of approximately two. Moreover, no other filter-based approach can provide a superior enhancement of these signatures. Applying our algorithm to WMAP 7-year observations, we detect eight new candidate bubble collision signatures for follow-up analysis.

McEwen, J. D.; Feeney, S. M.; Johnson, M. C.; Peiris, H. V.

2012-05-01

335

The Origin of Cosmic Rays: What can GLAST Say?  

NASA Technical Reports Server (NTRS)

Gamma rays in the band from 30 MeV to 300 GeV, used in combination with direct measurements and with data from radio and X-ray bands, provide a powerful tool for studying the origin of Galactic cosmic rays. Gamma-ray Large Area Space Telescope (GLAST) with its fine 10-20 arcmin angular resolution will be able to map the sites of acceleration of cosmic rays and their interactions with interstellar matter, It will provide information that is necessary to study the acceleration of energetic particles in supernova shocks, their transport in the interstellar medium and penetration into molecular clouds.

Ormes, Jonathan F.; Digel, Seith; Moskalenko, Igor V.; Moiseev, Alexander; Williamson, Roger

2000-01-01

336

MDAC solar cosmic ray experiment on OGO-6  

NASA Technical Reports Server (NTRS)

The instrumentation of the OGO-F solar cosmic ray experiment is described and results of data obtained during the satellite lifetime from launch on June 5, 1969, through September, 1970, and discussed.

Masley, A. J.

1973-01-01

337

The Determination of the Muon Magnetic Moment from Cosmic Rays  

ERIC Educational Resources Information Center

Describes an experiment suited for use in an advanced laboratory course in particle physics. The magnetic moment of cosmic ray muons which have some polarization is determined with an error of about five percent. (Author/GS)

Amsler, C.

1974-01-01

338

An Empirical Model for Determination of the Cosmic Ray Spectra  

NASA Astrophysics Data System (ADS)

The high-energy charged particles entering the Earth's environment from interplanetary space have the significant effect on the space weather. We propose an improved model, which generalizes the differential D(E) and integral D(>E) spectra of galactic (GCR) and anomalous cosmic ray (ACR) protons and heavier elements during the 11-year solar cycle. The model takes into account the cosmic ray (CR) modulation by the solar wind and numerous solar and heliospheric events during different levels of solar activity. Modulated energy spectrum of galactic cosmic rays is compared with force field approximation. The difference is in the order of 1.5 %. The model solutions are compared with IMAX-92, CAPRICE-94 and AMS-98 measurements. This computed analytical model gives practical possibility for investigation of experimental data from measurements of galactic cosmic rays and their anomalous component. The obtained parameters are used for determination the profiles of the ionization in the ionosphere and middle atmosphere.

Buchvarova, M.; Velinov, P.

2006-12-01

339

UNDERSTANDING TeV-BAND COSMIC-RAY ANISOTROPY  

SciTech Connect

We investigate the temporal and spectral correlations between flux and anisotropy fluctuations of TeV-band cosmic rays in light of recent data taken with IceCube. We find that for a conventional distribution of cosmic-ray sources, the dipole anisotropy is higher than observed, even if source discreteness is taken into account. Moreover, even for a shallow distribution of galactic cosmic-ray sources and a reacceleration model, fluctuations arising from source discreteness provide a probability only of the order of 10% that the cosmic-ray anisotropy limits of the recent IceCube analysis are met. This probability estimate is nearly independent of the exact choice of source rate, but generous for a large halo size. The location of the intensity maximum far from the Galactic Center is naturally reproduced.

Pohl, Martin [DESY, D-15738 Zeuthen (Germany)] [DESY, D-15738 Zeuthen (Germany); Eichler, David, E-mail: pohlmadq@gmail.com, E-mail: eichler@bgu.ac.il [Physics Department, Ben-Gurion University, Be'er-Sheva 84105 (Israel)] [Physics Department, Ben-Gurion University, Be'er-Sheva 84105 (Israel)

2013-03-20

340

Cosmic rays from ground level to space: South African perspective  

NASA Astrophysics Data System (ADS)

In South Africa, cosmic rays have been observed since the late 1950's. At present four cos-mic ray detectors, called neutron monitors, are been operated, with one in Antarctica and one in Namibia. These relative high energy measurements contribute significantly to the under-standing of the propagation of cosmic rays from the galaxy, through the heliosphere to Earth, and then through its magnetosphere and atmosphere. They therefore also contribute to the study of space weather and space climate. Since cosmic rays of lower energies are cut-off by the magnetosphere and atmosphere as protective barriers, they must be observed in space. In this context, South Africa has given the first steps with a newly created Space Agency, and subsequent proposals for future micro-satellites. A progress report on this challenge will be presented.

Potgieter, Marius

341

Modelling ground and space based cosmic ray observations  

NASA Astrophysics Data System (ADS)

Galactic cosmic rays are high energy charged particles that permeate the interstellar envi-ronment. They are subjected to a variety of highly time dependent physical processes when they enter the heliosphere. These processes cause the cosmic ray spectrum and intensities to change as a function of position, time and energy, referred to as heliospheric modulation. This modulation of cosmic rays manifests in observations, both ground and space based. In order to interpret these observations, much effort is put into modelling these modulation processes. This leads to a deeper understanding, not only of the physical processes that shape cosmic ray modulation, but also the heliospheric medium itself. With the emphasis on developing countries with limited funding and resources, it is also shown that numerical modelling studies offer a relatively cost-effective way to make a considerable contribution to space physics, and that modelling studies provide a valuable tool in interpreting both ground and space based observations.

Toit Strauss, Du; Potgieter, Marius; Ferreira, Stefan

342

Thunderstorms, cosmic rays, and solar-lunar influences  

SciTech Connect

A study of cosmic rays and thunderstorm frequency has shown a decrease in thunderstorms at the time of high cosmic rays and an increase in thunderstorms 2-4 days later. This was done by superposed epoch analysis of thunderstorms over the eastern two thirds of the United States for 1957-1976. When data for spring and fall months were used, the minimum deepened. When high cosmic rays near full and new moon for these months were key days, the minimum deepened again and was significant at less than the 0.01% level. It is believed that when the Sun, Earth, and Moon are aligned, particulate matter in the lower stratosphere is modulated and acted upon by cosmic rays, bringing about an immediate decrease in thunderstorms.

Lethbridge, M.D.

1990-08-20

343

Cosmic Rays Variation Before Changes in Sun-Earth Environment  

NASA Astrophysics Data System (ADS)

Influence of cosmic rays variations on the Sun-Earth Environment has been observed before the changes in the atmospheric temperature, outbreak of influenza, cyclone, earthquake and tsunami. It has been recorded by Sun Observatory Heleospheric Observatory (SOHO) satellite data. Before the earthquake and tsunami the planetary indices (Kp) and Electron flux (E-flux) shows sudden changes followed by the atmospheric perturbations including very high temperature rise to sudden fall resulting snowfall in high altitude and rainfall in tropical areas. The active fault zones shows sudden faulting after the sudden drop in cosmic ray intensity and rise in Kp and E-flux. Besides the geo-environment the extraterrestrial influence on outbreak of H1N1 influenza has also been recorded based on the Mexico Cosmic ray data and its correlation with SOHO records. Distant stars have the potential to influence the heliophysical parameters by showering cosmic rays.

Mukherjee, S.

2011-12-01

344

On wave stability in relativistic cosmic-ray hydrodynamics  

NASA Technical Reports Server (NTRS)

Wave stability of a two-fluid hydrodynamical model describing the acceleration of cosmic rays by the first-order Fermi mechanism in relativistic, cosmic-ray-modified shocks is investigated. For a uniform background state, the short- and long-wavelength wave speeds are shown to interlace, thus assuring wave stability in this case. A JWKB analysis is performed to investigate the stability of short-wavelength thermal gas sound waves in the smooth, decelerating supersonic flow upstream of a relativistic, cosmic-ray-modified shock. The stability of the waves is assessed both in terms of the fluid velocity and density perturbations, as well as in terms of the wave action. The stability and interaction of the short-wavelength cosmic-ray coherent mode with the background flow is also studied.

Webb, G. M.

1989-01-01

345

Supernova envelope shock origin of cosmic rays: a review  

SciTech Connect

The hydrodynamic shock origin of cosmic rays in the envelope of a Type I presupernova star is reviewed. The possibility of accelerating ultrahigh energy particles to greater than or equal to 10/sup 18/ eV is unique to the shock mechanism and currently no other suggested galactic or extragalactic site is likely. In this paper a review of the work leading to a renewed commitment to the origin of cosmic rays in the shock ejected envelope of supernova is given. The degree to which this interpretation applies to the origin of all cosmic rays is certainly uncertain and does not exclude the possibility of a fraction of the lower energy cosmic rays being accelerated in collisionless plasma shocks in the interstellar medium. 45 references, 3 figures.

Colgate, S.A.

1984-01-01

346

Hadronic Models for Cosmic Ray Physics: The FLUKA Code Solutions  

National Technical Information Service (NTIS)

FLUKA is a general purpose Monte Carlo transport and interaction code used for fundamental physics and for a wide range of applications. These include Cosmic Ray Physics (muons, neutrinos, EAS, underground physics), both for basic research and applied stu...

A. Fasso E. Gadioli G. Battistoni M. V. Garzelli P. R. Sala S. Muraro

2007-01-01

347

Cosmic Rays and Their Radiative Processes in Numerical Cosmology  

NASA Technical Reports Server (NTRS)

A cosmological hydrodynamic code is described, which includes a routine to compute cosmic ray acceleration and transport in a simplified way. The routine was designed to follow explicitly diffusive, acceleration at shocks, and second-order Fermi acceleration and adiabatic loss in smooth flows. Synchrotron cooling of the electron population can also be followed. The updated code is intended to be used to study the properties of nonthermal synchrotron emission and inverse Compton scattering from electron cosmic rays in clusters of galaxies, in addition to the properties of thermal bremsstrahlung emission from hot gas. The results of a test simulation using a grid of 128 (exp 3) cells are presented, where cosmic rays and magnetic field have been treated passively and synchrotron cooling of cosmic ray electrons has not been included.

Ryu, Dongsu; Miniati, Francesco; Jones, Tom W.; Kang, Hyesung

2000-01-01

348

A connection between star formation activity and cosmic rays in the starburst galaxy M82  

NASA Astrophysics Data System (ADS)

Although Galactic cosmic rays (protons and nuclei) are widely believed to be mainly accelerated by the winds and supernovae of massive stars, definitive evidence of this origin remains elusive nearly a century after their discovery. The active regions of starburst galaxies have exceptionally high rates of star formation, and their large size-more than 50 times the diameter of similar Galactic regions-uniquely enables reliable calorimetric measurements of their potentially high cosmic-ray density. The cosmic rays produced in the formation, life and death of massive stars in these regions are expected to produce diffuse ?-ray emission through interactions with interstellar gas and radiation. M82, the prototype small starburst galaxy, is predicted to be the brightest starburst galaxy in terms of ?-ray emission. Here we report the detection of >700-GeV ?-rays from M82. From these data we determine a cosmic-ray density of 250eVcm-3 in the starburst core, which is about 500 times the average Galactic density. This links cosmic-ray acceleration to star formation activity, and suggests that supernovae and massive-star winds are the dominant accelerators.

VERITAS Collaboration; Acciari, V. A.; Aliu, E.; Arlen, T.; Aune, T.; Bautista, M.; Beilicke, M.; Benbow, W.; Boltuch, D.; Bradbury, S. M.; Buckley, J. H.; Bugaev, V.; Byrum, K.; Cannon, A.; Celik, O.; Cesarini, A.; Chow, Y. C.; Ciupik, L.; Cogan, P.; Colin, P.; Cui, W.; Dickherber, R.; Duke, C.; Fegan, S. J.; Finley, J. P.; Finnegan, G.; Fortin, P.; Fortson, L.; Furniss, A.; Galante, N.; Gall, D.; Gibbs, K.; Gillanders, G. H.; Godambe, S.; Grube, J.; Guenette, R.; Gyuk, G.; Hanna, D.; Holder, J.; Horan, D.; Hui, C. M.; Humensky, T. B.; Imran, A.; Kaaret, P.; Karlsson, N.; Kertzman, M.; Kieda, D.; Kildea, J.; Konopelko, A.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; Lebohec, S.; Maier, G.; McArthur, S.; McCann, A.; McCutcheon, M.; Millis, J.; Moriarty, P.; Mukherjee, R.; Nagai, T.; Ong, R. A.; Otte, A. N.; Pandel, D.; Perkins, J. S.; Pizlo, F.; Pohl, M.; Quinn, J.; Ragan, K.; Reyes, L. C.; Reynolds, P. T.; Roache, E.; Rose, H. J.; Schroedter, M.; Sembroski, G. H.; Smith, A. W.; Steele, D.; Swordy, S. P.; Theiling, M.; Thibadeau, S.; Varlotta, A.; Vassiliev, V. V.; Vincent, S.; Wagner, R. G.; Wakely, S. P.; Ward, J. E.; Weekes, T. C.; Weinstein, A.; Weisgarber, T.; Williams, D. A.; Wissel, S.; Wood, M.; Zitzer, B.

2009-12-01

349

A connection between star formation activity and cosmic rays in the starburst galaxy M82.  

PubMed

Although Galactic cosmic rays (protons and nuclei) are widely believed to be mainly accelerated by the winds and supernovae of massive stars, definitive evidence of this origin remains elusive nearly a century after their discovery. The active regions of starburst galaxies have exceptionally high rates of star formation, and their large size-more than 50 times the diameter of similar Galactic regions-uniquely enables reliable calorimetric measurements of their potentially high cosmic-ray density. The cosmic rays produced in the formation, life and death of massive stars in these regions are expected to produce diffuse gamma-ray emission through interactions with interstellar gas and radiation. M82, the prototype small starburst galaxy, is predicted to be the brightest starburst galaxy in terms of gamma-ray emission. Here we report the detection of >700-GeV gamma-rays from M82. From these data we determine a cosmic-ray density of 250 eV cm(-3) in the starburst core, which is about 500 times the average Galactic density. This links cosmic-ray acceleration to star formation activity, and suggests that supernovae and massive-star winds are the dominant accelerators. PMID:19881491

2009-12-10

350

Cosmic Rays During the Most-Recent Sunspot Minimum  

NASA Astrophysics Data System (ADS)

During the sunspot minimum between solar cycles 23 and 24, galactic cosmic rays (GCR) reached the highest intensity seen during the spacecraft era. This was due in part to the lower open solar magnetic flux and slower solar wind seen during this period, compared to previous solar minima. The effects of cosmic-ray drifts along the heliospheric current sheet (HCS) has yet to be completely understood; but it is interesting to note that while the HCS was generally not as flat as one might expect given the very quiet Sun, it was at its flattest when the GCR intensity was at its highest. This is important because during this solar magnetic cycle, cosmic-ray protons drift into the heliosphere along the HCS. And, despite the unusually high GCR intensity during this solar minimum, the intensity of anomalous cosmic rays (ACR) was NOT seen to be as high as in previous sunspot minima. Moreover, the GCR electron intensity at the two Voyager spacecraft, which are both approaching the heliopause, is seen to be quite different. These observations lead to important questions regarding the transport of cosmic rays in the heliospheric magnetic field, which originates at the Sun. Particularly important is the transport of cosmic rays across the magnetic field, the role of the heliosheath in cosmic-ray modulation, drifts at the HCS, and the differences between ACRs and GCRs. In this talk, we will review our understanding of cosmic-ray transport in the solar and heliospheric magnetic field and discuss how observations will help resolve these recent puzzles and give constraints on transport parameters.

Giacalone, Joe; Jokipii, Jack; Kota, Jozsef

2012-07-01

351

Cosmic Rays During the Most-Recent Sunspot Minimum  

NASA Astrophysics Data System (ADS)

During the sunspot minimum between solar cycles 23 and 24, galactic cosmic rays (GCR) reached the highest intensity seen during the spacecraft era. This was due in part to the lower open solar magnetic flux and slower solar wind seen during this period, compared to previous solar minima. The effects of cosmic-ray drifts along the heliospheric current sheet (HCS) has yet to be completely understood; but it is interesting to note that while the HCS was generally not as flat as one might expect given the very quiet Sun, it was at its flattest when the GCR intensity was at its highest. This is important because during this solar magnetic cycle, cosmic-ray protons drift into the heliosphere along the HCS. And, despite the unusually high GCR intensity during this solar minimum, the intensity of anomalous cosmic rays (ACR) was NOT seen to be as high as in previous sunspot minima. Moreover, the GCR electron intensity at the two Voyager spacecraft, which are both approaching the heliopause, is seen to be quite different. These observations lead to important questions regarding the transport of cosmic rays in the heliospheric magnetic field, which originates at the Sun. Particularly important is the transport of cosmic rays across the magnetic field, the role of the heliosheath in cosmic-ray modulation, drifts at the HCS, and the differences between ACRs and GCRs. In this talk, we will review our understanding of cosmic-ray transport in the solar and heliospheric magnetic field and discuss how observations will help resolve these recent puzzles and give constraints on transport parameters.

Giacalone, J.; Jokipii, J. R.; Kota, J.

2011-12-01

352

Radio studies of cosmic rays in nearby galaxies  

Microsoft Academic Search

The study reviews the constraints on cosmic-ray electron sources and propagation as derived from radio continuum observations of galaxies. Special attention is given to the inferences which can be obtained from the radio continuum properties of spiral galaxies seen edge-on. It is found that a large fraction of the cosmic-ray electrons leave the source distribution, presumably associated with the thin

E. Hummel

1991-01-01

353

Preface: Centenary symposium 2012: Discovery of cosmic rays  

NASA Astrophysics Data System (ADS)

This meeting was at once a historical review of the developments during the 100 years since the discovery of cosmic rays in 1912 by Victor Hess, a consolidation and summary of the current new data and understanding, and a look into the future of the field of cosmic ray research. The meeting was held at the University of Denver, June 26-28, 2012. The papers and abstracts from this meeting constitute the contents of this volume of papers.

Ormes, Jonathan F.

2013-02-01

354

Large vessel imaging using cosmic-ray muons  

Microsoft Academic Search

Cosmic-ray muons are assessed for their practical use in the tomographic imaging of the internal composition of large vessels over 2m in diameter. The technique is based on the attenuation and scattering of cosmic-ray muons passing through a vessel and has advantages over photon-based methods of tomography that it is extendable to object containing high-density materials over many tens of

P. M. Jenneson

2004-01-01

355

Energy losses of galactic cosmic rays in the interplanetary medium.  

NASA Technical Reports Server (NTRS)

Using realistic models of cosmic-ray propagation in interplanetary space we present, for electrons, protons and helium nuclei of a given energy near earth, calculations of their distribution in energy before entering the solar cavity and their mean energy loss. Interplanetary conditions appropriate for the epochs 1965 and 1969 have been used. Cosmic-ray energies in the range of 20 to 1000 MeV/nucleon have been considered.

Urch, I. H.; Gleeson, L. J.

1973-01-01

356

The effect of cosmic rays on thunderstorm electricity  

NASA Technical Reports Server (NTRS)

The inflow of charges of small ions, formed by cosmic rays, into thunderstorm cells is estimated on the basis of rocket measurements of ionic concentrations below 90 km. Out of the two processes that form the thunderstorm charge (generation and separation of charges), the former is supposed to be caused by cosmic rays, and the nature of separation is assumed to be the same as in other thunderstorm theories.

Bragin, Y. A.

1975-01-01

357

Cosmic rays and changes in atmospheric infra-red transmission  

NASA Astrophysics Data System (ADS)

Recent work by Aplin and Lockwood (2013) [1] was interpreted by them as showing that there is a multiplying ratio of order 1012 for the infra-red energy absorbed in the ionization produced by cosmic rays in the atmosphere to the energy content of the cosmic rays themselves. We argue here that the interpretation of the result in terms of infra-red absorption by ionization is incorrect and that the result is therefore most likely due to a technical artefact.

Erlykin, A. D.; Sloan, T.; Wolfendale, A. W.

2014-05-01

358

The Acceleration Mechanism of Anomalous Cosmic Rays  

NASA Astrophysics Data System (ADS)

This paper reviews our current understanding of the acceleration mechanism of anomalous cosmic rays (ACRs). ACRs were first discovered in the early 1970s and soon afterwards it was recognized that they were accelerated interstellar pickup ions that obtained most of their energization in the outer heliosphere. Their observed composition and charge state suggest they are accelerated to over 200 MeV total energy in about a year. Diffusive shock acceleration at the solar-wind termination shock, which provided a natural explanation for spacecraft observations prior to the Voyager crossings of the termination shock in 2004 and 2007, was the long-held paradigm for the acceleration mechanism. But when both Voyagers crossed the shock, the ACR energy spectrum remained modulated, suggesting a source more distant than the shock. While shock acceleration remains a popular mechanism, other ideas have emerged recently to explain the observations. This review focuses on three main acceleration mechanisms that have been proposed: (a) acceleration at the termination shock including new effects such as the global blunt-shape of the shock and large-scale turbulence, (b) acceleration by magnetic reconnection in the heliosheath, and (c) acceleration by diffusive compression acceleration in the heliosheath.

Giacalone, J.; Drake, J. F.; Jokipii, J. R.

2012-11-01

359

A Cosmic Ray Telescope For Educational Purposes  

SciTech Connect

Cosmic ray detectors are widely used, for educational purposes, in order to motivate students to the physics of elementary particles and astrophysics. Using a 'telescope' of scintillation counters, the directional characteristics, diurnal variation, correlation with solar activity, can be determined, and conclusions about the composition, origin and interaction of elementary particles with the magnetic field of earth can be inferred. A telescope was built from two rectangular scintillator panels with dimensions: 91.6x1.9x3.7 cm{sup 3}. The scintillators are placed on top of each other, separated by a fixed distance of 34.6 cm. They are supported by a wooden frame which can be rotated around a horizontal axis. Direction is determined by the coincidence of the signals of the two PMTs. Standard NIM modules are used for readout. This device is to be used in the undergraduate nuclear and particle physics laboratory. The design and construction of the telescope as well as some preliminary results are presented.

Voulgaris, G.; Kazanas, S.; Chamilothoris, I. [Department of Physics, National and Kapodistrian University of Athens (Greece)

2010-01-21

360

Relativistic cosmic rays and corotating interaction regions  

NASA Technical Reports Server (NTRS)

The relationships between relativistic galactic cosmic ray intensity variations and corotating interaction regions (CIRs) are examined. Times of CIRs overtaking the earth as indicated by Pioneer 10 and 11 plasma and field observations are compared with nucleonic intensities recorded at the Thule and McMurdo polar stations in a superposed epoch analysis, with the centers of the CIR as zero days. Results indicate a decrease in intensity around the zero days, as well as a maximum around the ninth day and a general upward trend from days -13 to 13. Further examination reveals the observed features to be present only for those CIR- associated streams in which a neutral sheet is embedded. In contrast, superposed epoch analysis of the geomagnetic Ap index with respect to CIR epochs reveals CIRs both with and without neutral sheets to produce geomagnetic storms, although the peak increase in Ap index is greater for neutral-sheet-associated CIRs. Results suggest that the CIRs modulate high-energy particle intensities by means of drifts related to neutral sheets, although diffusion effects cannot yet be ruled out.

Duggal, S. P.; Pomerantz, M. A.; Tsao, C. H.; Tsurutani, B. T.; Smith, E. J.

1981-01-01

361

The origin of galactic cosmic rays  

NASA Astrophysics Data System (ADS)

Initial discovery of Cosmic Rays (CRs) dates back to a century ago (1912). Their identification as particles rather than radiation dates to about 20 years later and in 20 more years also the first suggestion that they were associated with SNRs was in place. The basic mechanism behind their acceleration was suggested almost 40 years ago. Much work has been done since then with regard to the aim of proving that both the acceleration mechanism and site are well-understood, but no definite proof has been obtained: in spite of impressive progress of both theory and observations, the evidence in support of the commonly accepted interpretation is only circumstantial. In the following, I will try to make the point on where we stand in terms of how our theories confront with data. I will review recent progress on the subject and try pointing the avenues to pursue in order to gather new proofs, if not a smoking gun evidence of the origin of Galactic CRs.

Amato, Elena

2014-05-01

362

Development of Ultra High-Energy Cosmic Ray Research  

NASA Astrophysics Data System (ADS)

The discovery of extensive air showers by Rossi, Schmeiser, Bothe, Kolhörster and Auger at the end of the 1930s, facilitated by the coincidence technique of Bothe and Rossi, led to fundamental contributions in the field of cosmic ray physics and laid the foundation for high-energy particle physics. Soon after World War II a cosmic ray group at MIT in the USA pioneered detailed investigations of air shower phenomena and their experimental skill laid the foundation for many of the methods and much of the instrumentation used today. Soon interests focused to the highest energies requiring much larger detectors to be operated. The first detection of air fluorescence light by Japanese and US groups in the early 1970s marked an important experimental breakthrough towards this end as it allowed huge volumes of atmosphere to be monitored by optical telescopes. Radio observations of air showers, pioneered in the 1960s, are presently experiencing a renaissance and may revolutionise the field again. In the last 7 decades the research has seen many ups but also a few downs. However, the example of the Cygnus X-3 story demonstrated that even non-confirmable observations can have a huge impact by boosting new instrumentation to make discoveries and shape an entire scientific community.

Kampert, Karl-Heinz; Watson, Alan A.

363

Simulations of black hole air showers in cosmic ray detectors  

SciTech Connect

We present a comprehensive study of TeV black hole events in Earth's atmosphere originated by cosmic rays of very high energy. An advanced fortran Monte Carlo code is developed and used to simulate black hole extensive air showers from ultrahigh-energy neutrino-nucleon interactions. We investigate the characteristics of these events, compare the black hole air showers to standard model air showers, and test different theoretical and phenomenological models of black hole formation and evolution. The main features of black hole air showers are found to be independent of the model considered. No significant differences between models are likely to be observed at fluorescence telescopes and/or ground arrays. We also discuss the tau 'double-bang' signature in black hole air showers. We find that the energy deposited in the second bang is too small to produce a detectable peak. Our results show that the theory of TeV-scale black holes in ultrahigh-energy cosmic rays leads to robust predictions, but the fine prints of new physics are hardly to be investigated through atmospheric black hole events in the near future.

Ahn, Eun-Joo; Cavaglia, Marco [Department of Astronomy and Astrophysics and Kavli Institute for Cosmological Physics, University of Chicago, 5640 S. Ellis Ave, Chicago, Illinois 60637 (United States); Department of Physics and Astronomy, University of Mississippi, University, Mississippi 38677-1848 (United States)

2006-02-15

364

Industrial radiography with cosmic-ray muons: A progress report  

NASA Astrophysics Data System (ADS)

Cosmic-ray produced muons arrive at the surface of the earth with enormous energies ranging up to 1012 GeV. There have been sporadic attempts to exploit their extreme penetration through matter to probe the internal structures of very large objects, including an Egyptian pyramid and a volcano but their very low intensity per unit area ( ?1 cm-2 per min) generally restricts the practicably attainable spatial resolution to large dimensions. Nevertheless the more intense low energy region of the muon spectrum has recently been shown to be capable of detecting high-Z objects with dimensions of the order of 10 cm hidden inside large transport containers in measurement times of minutes. These various developments have encouraged further studies of potential industrial uses of cosmic-ray muons in industrial applications. In order to gain maximum benefit from the low muon flux large area detectors are required and plastic scintillators offer useful advantages in size, cost and simplicity. Scintillator slabs up to 1 m2 square and 76.2 mm thick are undergoing testing for applications in the nuclear industry. The most direct approach employs photomultiplier tubes at each corner to measure the relative sizes of muon induced pulses to determine the location of each muon track passing through the scintillator. The performance of this technique is reported and its imaging potential is assessed.

Gilboy, W. B.; Jenneson, P. M.; Simons, S. J. R.; Stanley, S. J.; Rhodes, D.

2007-09-01

365

Cosmic Ray Anomalies from the MSSM?  

SciTech Connect

The recent positron excess in cosmic rays (CR) observed by the PAMELA satellite may be a signal for dark matter (DM) annihilation. When these measurements are combined with those from FERMI on the total (e{sup +} + e{sup -}) ux and from PAMELA itself on the {anti p}p ratio, these and other results are difficult to reconcile with traditional models of DM, including the conventional minimal Supergravity (mSUGRA) version of Supersymmetry even if boosts as large as 10{sup 3-4} are allowed. In this paper, we combine the results of a previously obtained scan over a more general 19-parameter subspace of the Minimal Supersymmetric Standard Model (MSSM) with a corresponding scan over astrophysical parameters that describe the propagation of CR. We then ascertain whether or not a good fit to this CR data can be obtained with relatively small boost factors while simultaneously satisfying the additional constraints arising from gamma ray data. We find that a specific subclass of MSSM models where the Lightest Supersymmetric Particle (LSP) is mostly pure bino and annihilates almost exclusively into {tau} pairs comes very close to satisfying these requirements. The lightest in this set of models is found to be relatively close in mass to the LSP and is in some cases the nLSP. These models lead to a significant improvement in the overall fit to the data by {approx}1 unit of {chi}{sup 2}/dof in comparison to the best fit without Supersymmetry while employing boosts in the range {approx}100-200. The implications of these models for future experiments are discussed.

Cotta, R.C.; /SLAC; Conley, J.A.; /Bonn U.; Gainer, J.S.; /Argonne /Northwestern U.; Hewett, J.L.; Rizzo, T.G.; /SLAC

2011-08-11

366

Precision Measurements of the Cosmic-Ray Composition  

NASA Astrophysics Data System (ADS)

Several experiments: AMS, ATIC, CREAM, PAMELA, etc., equipped with state-of-the art detectors, have recently presented or are going to present new results on the composition of the charged cosmic radiation with a significant improvement in statistics and systematics respect to existing data. From the energy spectra of antiparticles to the chemical composition and energy spectra of nuclei, these measurements have opened a new era of precision studies in cosmic rays that challenge our current understanding of cosmic-ray sources and acceleration and propagation mechanisms in the Galaxy. In this talk we will review these experiments and present their most recent scientific results.

Boezio, Mirko

2012-03-01

367

A New Measurement of the Cosmic X-ray Background  

SciTech Connect

I present a new analytical description of the cosmic X-ray background (CXRB) spectrum in the 1.5-200 keV energy band, obtained by combining the new measurement performed by the Swift X-ray telescope (XRT) with the recently published Swift burst alert telescope (BAT) measurement. A study of the cosmic variance in the XRT band (1.5-7 keV) is also presented. I find that the expected cosmic variance (expected from LogN-LogS) scales as {omega}{sup -0.3}(where {omega} is the surveyed area) in very good agreement with XRT data.

Moretti, A. [INAF-Osservatorio Astronomico di Brera v. E. Bianchi 46 23807 Merate (Italy)

2009-05-11

368

Effect of re-acceleration on cosmic ray components  

NASA Technical Reports Server (NTRS)

Reacceleration of cosmic rays in interstellar space has been studied in detail in order to examine the behavior of the ratios of secondary to primary nuclei in cosmic radiation. It is found that modest acceleration in a confinement region, where particles escape more freely at high energies, provides a better fit to the observed data. The effect of reacceleration on the spectral shape of proton and helium components of cosmic rays has been studied. The examination of two different models has shown that reacceleration provides a poor fit to the observed proton data.

Stephens, S. A.; Golden, R. L.

1989-01-01

369

Study of Cosmic Ray Muon Flux Variation with Atmospheric Weather  

NASA Astrophysics Data System (ADS)

Global climate change, driven by a variety of natural factors both on the planet and from outer space, has been a constant throughout the history of the earth. The variability of and interactions among these factors have been researched for decades. The relationships between cosmic ray radiation and other climate factors have been studied by many researchers, such as atmospheric pressure and temperature [1], low cloud coverage [2], and ozone depletion [3], etc. Over the past several years, various cosmic ray telescopes were built and have been measuring long-term cosmic ray muon flux at different spots in Georgia State University (GSU), A series of correlations between cosmic ray muon flux and local atmospheric weather have been being studied. The preliminary results from our recent measurement and research will be presented. [4pt] [1] Serap Tilav, et al., Atmospheric Variations as Observed by IceCude, Proceedings of the 31st ICRC, (2009).[0pt] [2] Nigel D. March and Henrik Svensmark, Low Cloud Properties Influenced by Cosmic Rays, Phys. Rev. Lett. 85, 23 (2000).[0pt] [3] Q.-B. Lu, Correlation between Cosmic Rays and Ozone Depletion, Phys. Rev. Lett. 102, 118501 (2009).

Zhang, Xiaohang; Dayananda, Mathes; He, Xiaochun

2012-03-01

370

A local recent supernova - Evidence from X-rays, Al-26 radioactivity and cosmic rays  

NASA Technical Reports Server (NTRS)

Possible ways in which cosmic rays could have been contaminated by a local recent supernova are discussed, and ways in which this contamination may be affecting interpretation of Al-26 gamma radiation and locally observed cosmic rays as samples of the average Galactic distribution are considered. Mass spectra of cosmic rays are examined to see whether there is enrichment by a population arising from supernova preacceleration. The reinterpretation of the anomalous component in terms of a local supernova model is addressed.

Clayton, Donald D.; Cox, Donald P.; Michel, Curtis F.

1986-01-01

371

Relationship between the galactic matter distribution, cosmic-ray dynamics, and gamma-ray production  

Microsoft Academic Search

Theoretical considerations and analysis of the results of ..gamma..-ray astronomy suggest that the galactic cosmic rays are dynamically coupled to the interstellar matter through the magnetic fields; hence the the cosmic-ray density should be enhanced where the matter density is greatest on the scale of galactic arms. This concept has been explored in a galactic model using recent 21 cm

D. A. Kniffen; C. E. Fichtel; D. J. Thompson

1977-01-01

372

Separation of the electron and proton cosmic-ray components by means of a calorimeter in the PAMELA satellite-borne experiment for the case of particle detection within a large aperture  

SciTech Connect

The PAMELA satellite-borne experiment is designed to study cosmic rays over a broad energy range. The apparatus has been in near-Earth cosmic space from June 2006 to the present time. It is equipped with a magnetic spectrometer for determining the sign of the particle charge and rigidity. In solving some problems, however, information from the magnetic spectrometer becomes inaccessible, so that it is necessary to employ a calorimeter to separate the electron and nuclear cosmic-ray components. A procedure for separating these components for particles arriving off the magnetic-spectrometer aperture is considered.

Karelin, A. V., E-mail: karelin@hotbox.ru; Borisov, S. V.; Voronov, S. A.; Malakhov, V. V. [National Research Nuclear University MEPhI (Russian Federation)

2013-06-15

373

Galactic Cosmic Rays from Supernova Remnants (I) - a Cosmic Ray Composition controlled by Volatility and Mass-to-Charge Ratio  

Microsoft Academic Search

This is the first of a series of papers analysing the Galactic Cosmic Ray\\u000acomposition and origin. We show that the Galactic Cosmic Ray source (GCRS)\\u000acomposition is best described in terms of (i) a general enhancement of the\\u000arefractory elements relative to the volatile ones, and (ii) among the volatile\\u000aelements, an enhancement of the heavier elements relative to

Donald C. Ellison

1997-01-01

374

Cosmic-ray record in solar system matter  

NASA Technical Reports Server (NTRS)

The interaction of galactic cosmic rays (GCR) and solar cosmic rays (SCR) with bodies in the solar system is discussed, and what the record of that interaction reveals about the history of the solar system is considered. The influence of the energy, charge, and mass of the particles on the interaction is addressed, showing long-term average fluxes of solar protons, predicted production rates for heavy-nuclei tracks and various radionuclides as a function of depth in lunar rock, and integral fluxes of protons emitted by solar flares. The variation of the earth's magnetic field, the gardening of the lunar surface, and the source of meteorites and cosmic dust are studied using the cosmic ray record. The time variation of GCR, SCR, and VH and VVH nuclei is discussed for both the short and the long term.

Reedy, R. C.; Arnold, J. R.; Lal, D.

1983-01-01

375

A full acceptance SSC detector: The cosmic-ray connection  

SciTech Connect

Bjorken has proposed the construction of a full acceptance SSC detector (FAD) with the capability of observing complete events, i.e., sensitive to all particles at all rapidities. We here draw attention to the fact that the particle physics capabilities of such an instrument can be exploited to resolve important issues in cosmic ray astrophysics. FAD can make a critical contribution to the search for the cosmic accelerator(s) of the highest energy cosmic rays. Also, unlike conventional central detectors, FAD can search for a variety of unusual phenomena associated with production of very forward particles in cosmic ray interactions with collision energy in excess of 10[sup 14]--10[sup 15] eV, i.e. [radical][ital s] larger than 1 TeV.

Halzen, F. (University of Wisconsin, Department of Physics, Madison, 530706 (United States))

1993-06-15

376

Radial Intensity Gradient of Galactic Cosmic Rays at Solar Maximum  

NASA Astrophysics Data System (ADS)

The spatial distribution of galactic cosmic rays in the heliosphere at solar maximum of Cicles 21, 22 and 23 are studied, using a two dimensional time-dependent model of the cosmic ray transport equation. We investigated the radial intensity gradient from 1 AU to the distant heliosphere and interpreted the data from IMP8, Voyagers 1/2, Pioneer 10 and balloon exper-iment BESS. In our model we considered the relevant physical processes that affect the cosmic radiation: diffusion, convection, addiabatic energy loss, drift and acceleration at the solar wind termination shock. We discussed the results and analyzed the implications of the different local insterstellar spectra and the strength of the shock on the distribution of cosmic rays inside the modulation region.

Caballero-Lopez, Rogelio A.; Morales-Olivares, Oscar G.

377

Galactic Cosmic Ray Modulation in the Heliosphere at Solar Maximum  

NASA Astrophysics Data System (ADS)

The spatial distribution of galactic cosmic rays in the heliosphere at solar maximum of Cycles 21, 22 and 23 are studied using a one dimensional model of the cosmic ray transport equation. We investigated the radial intensity gradients from 1 AU to the distant heliosphere and interpreted the data from IMP8, Voyagers 1/2, Pioneer 10 and balloon experiment BESS. In our model we considered three of the physical processes that affect the cosmic radiation: diffusion, convection and adiabatic energy loss. Our analysis indicates that adiabatic energy loss plays an important role in the radial distribution of galactic cosmic ray in the inner heliosphere, while in the outer region the diffusion and convection are the relevant processes.

Morales-Olivares, O. G.; Caballero–López, R. A.

378

PAMELA measurements of cosmic-ray proton and helium spectra.  

PubMed

Protons and helium nuclei are the most abundant components of the cosmic radiation. Precise measurements of their fluxes are needed to understand the acceleration and subsequent propagation of cosmic rays in our Galaxy. We report precision measurements of the proton and helium spectra in the rigidity range 1 gigavolt to 1.2 teravolts performed by the satellite-borne experiment PAMELA (payload for antimatter matter exploration and light-nuclei astrophysics). We find that the spectral shapes of these two species are different and cannot be described well by a single power law. These data challenge the current paradigm of cosmic-ray acceleration in supernova remnants followed by diffusive propagation in the Galaxy. More complex processes of acceleration and propagation of cosmic rays are required to explain the spectral structures observed in our data. PMID:21385721

Adriani, O; Barbarino, G C; Bazilevskaya, G A; Bellotti, R; Boezio, M; Bogomolov, E A; Bonechi, L; Bongi, M; Bonvicini, V; Borisov, S; Bottai, S; Bruno, A; Cafagna, F; Campana, D; Carbone, R; Carlson, P; Casolino, M; Castellini, G; Consiglio, L; De Pascale, M P; De Santis, C; De Simone, N; Di Felice, V; Galper, A M; Gillard, W; Grishantseva, L; Jerse, G; Karelin, A V; Koldashov, S V; Krutkov, S Y; Kvashnin, A N; Leonov, A; Malakhov, V; Malvezzi, V; Marcelli, L; Mayorov, A G; Menn, W; Mikhailov, V V; Mocchiutti, E; Monaco, A; Mori, N; Nikonov, N; Osteria, G; Palma, F; Papini, P; Pearce, M; Picozza, P; Pizzolotto, C; Ricci, M; Ricciarini, S B; Rossetto, L; Sarkar, R; Simon, M; Sparvoli, R; Spillantini, P; Stozhkov, Y I; Vacchi, A; Vannuccini, E; Vasilyev, G; Voronov, S A; Yurkin, Y T; Wu, J; Zampa, G; Zampa, N; Zverev, V G

2011-04-01

379

Propagation of Cosmic Rays: Nuclear Physics in Cosmic-ray Studies  

NASA Technical Reports Server (NTRS)

The nuclei fraction in cosmic rays (CR) far exceeds the fraction of other CR species, such as antiprotons, electrons, and positrons. Thus the majority of information obtained from CR studies is based on interpretation of isotopic abundances using CR propagation models where the nuclear data and isotopic production cross sections in p- and alpha-induced reactions are the key elements. This paper presents an introduction to the astrophysics of CR and diffuse gamma-rays and dimsses some of the puzzles that have emerged recently due to more precise data and improved propagation models. Merging with cosmology and particle physics, astrophysics of CR has become a very dynamic field with a large potential of breakthrough and discoveries in the near fume. Exploiting the data collected by the CR experiments to the fullest requires accurate nuclear cross sections.

Moskalenko, Igor V.; Strong, Andrew W.; Mashnik, Stepan G.

2004-01-01

380

Alteration of Organic Compounds in Small Bodies and Cosmic Dusts by Cosmic Rays and Solar Radiation  

NASA Astrophysics Data System (ADS)

A wide variety of complex organic compounds have been detected in extraterrestrial bodies like carbonaceous chondrites and comets, and their roles in the generation of terrestrial life are discussed. It was suggested that organics in small bodies were originally formed in ice mantles of interstellar dusts in dense cloud. Irradiation of frozen mixture of possible interstellar molecules including CO (or CH _{3}OH), NH _{3} and H _{2}O with high-energy particles gave complex amino acid precursors with high molecular weights [1]. Such complex organic molecules were taken in planetesimals or comets in the early solar system. In prior to the generation of the terrestrial life, extraterrestrial organics were delivered to the primitive Earth by such small bodies as meteorites, comets and space dusts. These organics would have been altered by cosmic rays and solar radiation (UV, X-rays) before the delivery to the Earth. We examined possible alteration of amino acids, their precursors and nucleic acid bases in interplanetary space by irradiation with high energy photons and heavy ions. A mixture of CO, NH _{3} and H _{2}O was irradiated with high-energy protons from a van de Graaff accelerator (TIT, Japan). The resulting products (hereafter referred to as CAW) are complex precursors of amino acids. CAW, amino acids (dl-Isovaline, glycine), hydantoins (amino acid precursors) and nucleic acid bases were irradiated with continuous emission (soft X-rays to IR; hereafter referred to as soft X-rays irradiation) from BL-6 of NewSUBARU synchrotron radiation facility (Univ. Hyogo). They were also irradiated with heavy ions (eg., 290 MeV/u C ^{6+}) from HIMAC accelerator (NIRS, Japan). After soft X-rays irradiation, water insoluble materials were formed. After irradiation with soft X-rays or heavy ions, amino acid precursors (CAW and hydantoins) gave higher ratio of amino acids were recovered after hydrolysis than free amino acids. Nucleic acid bases showed higher stability than free amino acids. Complex amino acid precursors with high molecular weights could be formed in simulated dense cloud environments. They would have been altered in the early solar system by irradiation with soft X-rays from the young Sun, which caused increase of hydrophobicity of the organics of interstellar origin. They were taken up by parent bodies of meteorites or comets, and could have been delivered to the Earth by meteorites, comets and cosmic dusts. Cosmic dusts were so small that they were directly exposed to the solar radiation, which might be critical for the survivability of organics in them. In order to evaluate the roles of space dusts as carriers of bioorganic compounds to the primitive Earth, we are planning the Tanpopo Mission, where collection of cosmic dusts by using ultra low-density aerogel, and exposure of amino acids and their precursors for years are planned by utilizing the Japan Experimental Module / Exposed Facility of the ISS [2]. The mission is now scheduled to start in 2013. We thank Dr. Katsunori Kawasaki of Tokyo Institute of Technology, and Dr. Satoshi Yoshida of National Institute of Radiological Sciences for their help in particles irradiation. We also thank to the members of JAXA Tanpopo Working Group (PI: Prof. Akihiko Yamagishi) for their helpful discussion. [1] K. Kobayashi, et al., in ``Astrobiology: from Simple Molecules to Primitive Life,'' ed. by V. Basiuk, American Scientific Publishers, Valencia, CA, (2010), pp. 175-186. [2] K. Kobayashi, et al., Trans. Jpn. Soc. Aero. Space Sci., in press (2012).

Kobayashi, Kensei; Kaneko, Takeo; Mita, Hajime; Obayashi, Yumiko; Takahashi, Jun-ichi; Sarker, Palash K.; Kawamoto, Yukinori; Okabe, Takuto; Eto, Midori; Kanda, Kazuhiro

2012-07-01

381

Cosmic Ray Studies with the Fermi Gamma-ray Space Telescope Large Area Telescope  

NASA Technical Reports Server (NTRS)

The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope provides both direct and indirect measurements of galactic cosmic rays (CR). The LAT high-statistics observations of the 7 GeV - 1 TeV electron plus positron spectrum and limits on spatial anisotropy constrain models for this cosmic-ray component. On a galactic scale, the LAT observations indicate that cosmic-ray sources may be more plentiful in the outer Galaxy than expected or that the scale height of the cosmic-ray diffusive halo is larger than conventional models. Production of cosmic rays in supernova remnants (SNR) is supported by the LAT gamma-ray studies of several of these, both young SNR and those interacting with molecular clouds.

Thompson, David J.; Baldini, L.; Uchiyama, Y.

2012-01-01

382

Cosmic Ray Studies with the Fermi Gamma-ray Space Telescope Large Area Telescope  

NASA Technical Reports Server (NTRS)

The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope provides both direct and indirect measurements of Galactic cosmic rays (CR). The LAT high-statistics observations of the 7 GeV - 1 TcV electron plus positron spectrum and limits on spatial anisotropy constrain models for this cosmic-ray component. On a Galactic scale, the LAT observations indicate that cosmic-ray sources may be more plentiful in the outer Galaxy than expected or that the scale height of the cosmic-ray diffusive halo is larger than conventional models. Production of cosmic rays in supernova remnants (SNR) is supported by the LAT gamma-ray studies of several of these, both young SNR and those interacting with molecular clouds.

Thompson, D. J.; Baldini, L.; Uchiyama, Y.

2011-01-01

383

Galactic Cosmic Rays and the Environment  

NASA Astrophysics Data System (ADS)

SH.3.6.14 Galactic Cosmic Rays and the Environment G. Cini Castagnoli, G. Bonino, P. Della Monica, C. Taricco Istituto di Cosmogeofisica, CNR, Corso Fiume 4, 10133 Torino, Italy and Dipartimento di Fisica Generale, Università di Torino, Via P. Giuria 1, 10125 Torino Recently Svensmark and Friis-Christensen (1997) reported an indication that the Galactic Cosmic Rays (GCR) modulated by the solar wind may contribute to the variations in the formation of clouds, which in turn should follow the 11 y solar cycle. On the other hand experiments, conducted in vitro, on the variations of ?3C in symbiont bearing 1 foraminifera have shown that the carbon isotope fractionation from sea water, of the calcite of their shells, depends mainly on the photosynthetic activity (primary productivity) of the symbionts and therefore from the illumination level of their habitat. We have measured and analyzed (Cini Castagnoli et al., 1999) the ?3C profile of G. ruber in an Ionian sea 1 shallow water core very precisely dated. This allows us to acquire information on the ambient light level (connected to the solar irradiance modulation and to the cloud coverage) of the Gallipoli terrace in the past Millenium. The record (1205-1975 AD) of 200 points with time resolution 3.87 years shows a highly significant 11 y cyclicity covariant with Sunspots of amplitude 0.04 ‰ . A test for determining the ?3C-irradiance relation has been 1 13 performed by studying variations of ? C and the percentage annual number of rainy days during the last century in this region. Our results agree with the expectations on the basis of experiments performed in vitro on G. sacculifer ( on G. ruber is not available). The amplitude of the 11 y ?3C signal turns out to be of the order of 1.5 W/m2. This value seems to be 1 quite high (although of the same order) to be directly induced solely by changes in the solar constant, if in past times they were similar to those measured in space during solar cycles 22-23. The effect could be mediated by changes in clouds formation by GCR. We estimate that the cloudiness variations (from rainy days in our site) necessary to produce our ?3C 11 y signal is of ~ 3 % (peak to through) this value is in 1 agreement with the variations of the global cloud coverage between 1980 and 1995 connected to the climax neutron monitor GCR intensity modulation by the above mentioned authors. References Cini Castagnoli, G., Bernasconi, S., Bonino, G., Della Monica, P., & Taricco, C. 1999, Adv. Space Res., in press. Svensmark, H, & Friis-Christensen, E. 1997, J. Atmos. Sol. Terr. Phys. 59, 1225.

Castagnoli, G. Cini

384

Assessment of galactic cosmic ray models  

NASA Astrophysics Data System (ADS)

Among several factors involved in the development of a manned space mission concept, the astronauts' health is a major concern that needs to be considered carefully. Galactic cosmic rays (GCRs), which mainly consist of high-energetic nuclei ranging from hydrogen to iron and beyond, pose a major radiation health risk in long-term space missions. It is therefore required to assess the radiation exposure of astronauts in order to estimate their radiation risks. This can be done either by performing direct measurements or by making computer based simulations from which the dose can be derived. A necessary prerequisite for an accurate estimation of the exposure using simulations is a reliable description of the GCR spectra. The aim of this work is to compare GCR models and to test their applicability for the exposure assessment of astronauts. To achieve this, commonly used models capable of describing both light and heavy GCR particle spectra were evaluated by investigating the model spectra for various particles over several decades. The updated Badhwar-O'Neill model published in the year 2010, CREME2009 which uses the International Standard model for GCR, CREME96 and the Burger-Usoskin model were examined. Hydrogen, helium, oxygen and iron nuclei spectra calculated by the different models are compared with measurements from various high-altitude balloon and space-borne experiments. During certain epochs in the last decade, there are large discrepancies between the GCR energy spectra described by the models and the measurements. All the models exhibit weaknesses in describing the increased GCR flux that was observed in 2009-2010.

Mrigakshi, Alankrita Isha; Matthiä, Daniel; Berger, Thomas; Reitz, Günther; Wimmer-Schweingruber, Robert F.

2012-08-01

385

Gamma-Ray, Cosmic Ray and Neutrino Tests of Lorentz Invariance and Quantum Gravity Models  

NASA Technical Reports Server (NTRS)

High-energy astrophysics observations provide the best possibilities to detect a very small violation of Lorentz invariance such as may be related to the structure of space-time near the Planck scale of approximately 10(exp -35) m. I will discuss here the possible signatures of Lorentz invariance violation (LIV) from observations of the spectra, polarization, and timing of gamma-rays from active galactic nuclei and gamma-ray bursts. Other sensitive tests are provided by observations of the spectra of ultrahigh energy cosmic rays and neutrinos. Using the latest data from the Pierre Auger Observatory one can already derive an upper limit of 4.5 x 10(exp -23) to the amount of LIV of at a proton Lorentz factor of approximately 2 x 10(exp 11). This result has fundamental implications for quantum gravity models. I will also discuss the possibilities of using more sensitive space based detection techniques to improve searches for LIV in the future.

Stecker, Floyd

2011-01-01

386

Galaxy Mergers as a Source of Cosmic Rays, Neutrinos, and Gamma Rays  

NASA Astrophysics Data System (ADS)

We investigate the shock acceleration of particles in massive galaxy mergers or collisions, and show that cosmic rays (CRs) can be accelerated up to the second knee energy ~0.1-1 EeV and possibly beyond, with a hard spectral index of ? ? 2. Such CRs lose their energy via hadronuclear interactions within a dynamical timescale of the merger shock, producing gamma rays and neutrinos as a by-product. If ~10% of the shock dissipated energy goes into CR acceleration, some local merging galaxies will produce gamma-ray counterparts detectable by the Cherenkov Telescope Array. Also, based on the concordance cosmology, where a good fraction of the massive galaxies experience a major merger in a cosmological timescale, the neutrino counterparts can constitute ~20%-60% of the isotropic background detected by IceCube.

Kashiyama, Kazumi; Mészáros, Peter

2014-07-01

387

Search for antimatter with the AMS cosmic ray detector  

NASA Astrophysics Data System (ADS)

Antimatter search results of the Alpha Magnetic Spectrometer (AMS) detector are presented. About 108 triggers were collected in the 1998 precursor flight onboard space shuttle Discovery. This ten day mission exposed the detector on a 51.7° orbit at an altitude around 350km. Identification of charged cosmic rays is achieved by multiple energy loss and time-of-flight measurements. Bending inside the 0.15T magnetic volume yields a measurement of the absolute value of the particle's rigidity. The supplemental knowledge of the sense of traversal identifies the sign of the charge. In the rigidity range 1 < R < 140 GV no antinucleus at any rigidity was detected, while 2.86 × 106 helium and 1.65 × 105 heavy nuclei were precisely measured. Hence, upper limits on the flux ratio Zbar/Z are given. Different prior assumptions on the antimatter spectrum are considered and corresponding limits are given.

Cristinziani, Markus

2003-01-01

388

On Cosmic Rays, IP Structures and Geospace Consequences During WHI  

NASA Astrophysics Data System (ADS)

This work presents some observations during the period of the Whole Heliosphere Interval (WHI) of the effects of interplanetary (IP) structures on the near-Earth space using three sets of observations: magnetic field and plasma from the Advanced Composition Explorer (ACE) satellite, ground-based cosmic ray data from the Global Muon Detection Network (GMDN) and geomagnetic indices (Disturbance storm-time, Dst, and auroral electrojet index, AE). Since WHI was near minimum solar activity, high speed streams and corotating interaction regions (CIRs) were the dominant structures observed in the interplanetary space surrounding Earth. Very pronounced geomagnetic effects are shown to be correlated to CIRs, especially because they can cause the so-called High-Intensity Long-Duration Continuous AE Activity (HILDCAAs) - Tsurutani and Gonzalez (1987). At least a few high speed streams can be identified during the period of WHI. The focus here is to characterize these IP structures and their geospace consequences.

Lago, A. Dal; Guarnieri, F. L.; da Silva, M. R.; Gonzalez, W. D.; Braga, C. R.; Schuch, N. J.; Munakata, K.; Kato, C.; Bieber, J. W.; Kuwabara, T.; Tokumaru, M.; Duldig, M. L.; Humble, J. E.

2010-11-01

389

A measurement of the antiproton flux in the cosmic rays  

NASA Technical Reports Server (NTRS)

A balloon-borne instrument has been used to detect cosmic-ray antiprotons. These are identified topologically by the appearance of annihilation prongs in a thick lead-plate spark chamber. The initial recording of the data is enriched in potential antimatter events by a selective trigger. After a small subtraction for background, 14 identified antiprotons yield a flux of 1.7 plus or minus 0.00005 antiproton/(sq m ster sec MeV) between 130 and 320 MeV at the top of the atmosphere. When combined with higher energy antiproton flux measurements, this result indicates that the antiprotons have a spectrum whose shape is the same as that of the protons, but with a magnitude reduced by a factor of 1/3000.

Buffington, A.; Schindler, S. M.

1981-01-01

390

Winds, Clumps, and Interacting Cosmic Rays in M82  

NASA Astrophysics Data System (ADS)

We construct a family of models for the evolution of energetic particles in the starburst galaxy M82 and compare them to observations to test the calorimeter assumption that all cosmic ray energy is radiated in the starburst region. Assuming constant cosmic ray acceleration efficiency with Milky Way parameters, we calculate the cosmic-ray proton and primary and secondary electron/positron populations as a function of energy. Cosmic rays are injected with Galactic energy distributions and electron-to-proton ratio via Type II supernovae at the observed rate of 0.07 yr-1. From the cosmic ray spectra, we predict the radio synchrotron and ?-ray spectra. To more accurately model the radio spectrum, we incorporate a multiphase interstellar medium in the starburst region of M82. Our model interstellar medium is highly fragmented with compact dense molecular clouds and dense photoionized gas, both embedded in a hot, low density medium in overall pressure equilibrium. The spectra predicted by this one-zone model are compared to the observed radio and ?-ray spectra of M82. ?2 tests are used with radio and ?-ray observations and a range of model predictions to find the best-fit parameters. The best-fit model yields constraints on key parameters in the starburst zone of M82, including a magnetic field strength of ~250 ?G and a wind advection speed in the range of 300-700 km s-1. We find that M82 is a good electron calorimeter but not an ideal cosmic-ray proton calorimeter and discuss the implications of our results for the astrophysics of the far-infrared-radio correlation in starburst galaxies.

Yoast-Hull, Tova M.; Everett, John E.; Gallagher, J. S., III; Zweibel, Ellen G.

2013-05-01

391

WINDS, CLUMPS, AND INTERACTING COSMIC RAYS IN M82  

SciTech Connect

We construct a family of models for the evolution of energetic particles in the starburst galaxy M82 and compare them to observations to test the calorimeter assumption that all cosmic ray energy is radiated in the starburst region. Assuming constant cosmic ray acceleration efficiency with Milky Way parameters, we calculate the cosmic-ray proton and primary and secondary electron/positron populations as a function of energy. Cosmic rays are injected with Galactic energy distributions and electron-to-proton ratio via Type II supernovae at the observed rate of 0.07 yr{sup -1}. From the cosmic ray spectra, we predict the radio synchrotron and {gamma}-ray spectra. To more accurately model the radio spectrum, we incorporate a multiphase interstellar medium in the starburst region of M82. Our model interstellar medium is highly fragmented with compact dense molecular clouds and dense photoionized gas, both embedded in a hot, low density medium in overall pressure equilibrium. The spectra predicted by this one-zone model are compared to the observed radio and {gamma}-ray spectra of M82. {chi}{sup 2} tests are used with radio and {gamma}-ray observations and a range of model predictions to find the best-fit parameters. The best-fit model yields constraints on key parameters in the starburst zone of M82, including a magnetic field strength of {approx}250 {mu}G and a wind advection speed in the range of 300-700 km s{sup -1}. We find that M82 is a good electron calorimeter but not an ideal cosmic-ray proton calorimeter and discuss the implications of our results for the astrophysics of the far-infrared-radio correlation in starburst galaxies.

Yoast-Hull, Tova M.; Everett, John E.; Zweibel, Ellen G. [Department of Physics, University of Wisconsin-Madison, WI (United States); Gallagher, J. S. III, E-mail: yoasthull@wisc.edu [Department of Astronomy, University of Wisconsin-Madison, WI (United States)

2013-05-01

392

DE-EXCITATION NUCLEAR GAMMA-RAY LINE EMISSION FROM LOW-ENERGY COSMIC RAYS IN THE INNER GALAXY  

SciTech Connect

Recent observations of high ionization rates of molecular hydrogen in diffuse interstellar clouds point to a distinct low-energy cosmic-ray component. Supposing that this component is made of nuclei, two models for the origin of such particles are explored and low-energy cosmic-ray spectra are calculated, which, added to the standard cosmic-ray spectra, produce the observed ionization rates. The clearest evidence of the presence of such low-energy nuclei between a few MeV nucleon{sup -1} and several hundred MeV nucleon{sup -1} in the interstellar medium would be a detection of nuclear {gamma}-ray line emission in the range E {sub {gamma}} {approx} 0.1-10 MeV, which is strongly produced in their collisions with the interstellar gas and dust. Using a recent {gamma}-ray cross section compilation for nuclear collisions, {gamma}-ray line emission spectra are calculated alongside the high-energy {gamma}-ray emission due to {pi}{sup 0} decay, the latter providing normalization of the absolute fluxes by comparison with Fermi-LAT observations of the diffuse emission above E {sub {gamma}} = 0.1 GeV. Our predicted fluxes of strong nuclear {gamma}-ray lines from the inner Galaxy are well below the detection sensitivities of the International Gamma-Ray Astrophysics Laboratory, but a detection, especially of the 4.4 MeV line, seems possible with new-generation {gamma}-ray telescopes based on available technology. We also predict strong {gamma}-ray continuum emission in the 1-8 MeV range, which, in a large part of our model space for low-energy cosmic rays, considerably exceeds the estimated instrument sensitivities of future telescopes.

Benhabiles-Mezhoud, H.; Kiener, J.; Tatischeff, V. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, CNRS-IN2P3 and Universite Paris-Sud, F-91405 Orsay Campus (France)] [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, CNRS-IN2P3 and Universite Paris-Sud, F-91405 Orsay Campus (France); Strong, A. W., E-mail: Jurgen.Kiener@csnsm.in2p3.fr [Max-Planck Institut fuer extraterrestrische Physik, D-85748 Garching (Germany)

2013-02-15

393

Propagation Model for Cosmic Ray Species in the Galaxy  

NASA Technical Reports Server (NTRS)

During the last decade there have been a number of space and balloon experiments with improved sensivity and statistics, which impose stricter constraints on cosmic ray propagation models. Propagation is the main issue in the interpretation of such data as antiproton and positron fluxes in cosmic rays, and diffuse gamma-ray emission. We develop a new propagation model that reproduces measurements of secondary antiprotons as well as primary and secondary nuclei. We will present results of our calculation of CR propagation in the Galaxy for this model using the GALPROP code.

White, Nicholas E. (Technical Monitor); Moskalenko, I. V.; Jones, F. C.; Ptuskin, V. S.; Strong, A. W.; Mashnik, S. G.

2002-01-01

394

Transition radiation as a source of cosmic X-rays.  

NASA Technical Reports Server (NTRS)

It is shown that transition radiation generated during the passage of relativistic charged particles through interstellar grains can be an important source of cosmic X-rays. In order to account for recent X-ray observations below 300 eV by transition radiation, an energy density in interstellar space of about 10 eV per cu cm in 10 MeV electrons is required. This seems to rule out transition radiation as an important source of diffuse cosmic X-rays in any energy region.

Ramaty, R.; Bleach, R. D.

1972-01-01

395

Fermi LAT Observations of Cosmic-Ray Electrons.  

National Technical Information Service (NTIS)

Designed as a gamma-ray instrument, the LAT is a capable detector of high energy cosmic ray electrons. The LAT is composed of a 4x4 array of identical towers. Each tower has a Tracker and a Calorimeter module. Entire LAT is covered by segmented Anti-Coinc...

A. Moiseev

2011-01-01

396

Sources of cosmic rays and galactic diffuse gamma radiation  

NASA Astrophysics Data System (ADS)

The diffuse galactic gamma-ray spectrum measured by the EGRET experiment is interpreted within a scenario in which cosmic rays (CRs) are injected by three different kind of sources, (i) supernovae (SN) which explode into the interstellar medium (ISM), (ii) Red Supergiants (RSG), and (iii) Wolf-Rayet stars (WR), where the two latter explode into their pre-SN winds.

Casanova, S.; Biermann, P. L.; Engel, R.; Meli, A.; Ulrich, R.

397

Reviews of Topical Problems: the Study of Cosmic gamma Rays  

Microsoft Academic Search

CONTENTS 1. Introduction 630 2. Main Cosmic gamma-ray (CGR) Production Processes. Interaction of CGR with Interstellar and Intergalactic Matter 631 3. Methods of Study of CGR 632 4. Comparability of Experimental Results. Calibration of gamma Detectors 634 5. Conditions of CGR Study. Atmospheric and Local Backgrounds 635 6. Results of Diffuse CGR Measurement in Balloons. The gamma-ray Flux Extrapolated to

A. M. Gal'per; V. G. Kirillov-Ugryumov; B. I. Luchkov; O. F. Prilutskii

1972-01-01

398

Cosmological cosmic rays: Sharpening the primordial lithium problem  

Microsoft Academic Search

Cosmic structure formation leads to large-scale shocked baryonic flows which are expected to produce a cosmological population of structure-formation cosmic rays (SFCRs). Interactions between SFCRs and ambient baryons will produce lithium isotopes via +{sup 6,7}Li. This pre-galactic (but nonprimordial) lithium should contribute to the primordial Li measured in halo stars and must be subtracted in order to arrive to the

Brian D. Fields; Tijana Prodanovic

2007-01-01

399

Cosmological cosmic rays: Sharpening the primordial lithium problem  

Microsoft Academic Search

Cosmic structure formation leads to large-scale shocked baryonic flows which are expected to produce a cosmological population of structure-formation cosmic rays (SFCRs). Interactions between SFCRs and ambient baryons will produce lithium isotopes via alpha+alpha-->Li6,7. This pre-galactic (but nonprimordial) lithium should contribute to the primordial Li7 measured in halo stars and must be subtracted in order to arrive to the true

Tijana Prodanovic; Brian D. Fields

2007-01-01

400

Cosmic-ray modulation and the anamalous component  

NASA Technical Reports Server (NTRS)

Advances in the theory and observation of cosmic ray modulation and in studies of the anomalous component in cosmic radiation are reviewed from reports that appeared in the open literature during the years 1979 to 1982. Entries, which are primarily the work of American researchers, are cited under the following categories: (1) microscopic diffusion theory; (2) global modulation theory; (3) anomalous component; and (4) general modulation observation.

Jones, F. C.

1983-01-01

401

Cosmic rays, geomagnetic field and climate changes  

NASA Astrophysics Data System (ADS)

The possibility of a connection between cosmic radiation and climate has intrigued scientists for the past several decades. The recent studies of Friis -Christensen and Svensmark has shown an observed variation of 3-4% of the global cloud cover between 1980 and 1995 that appeared to be directly correlated with the change in galactic cosmic radiation flux over the solar cycle. However, in studies of this type, not only the solar cycle modulation of cosmic radiation must be considered, but also the changes in the cosmic radiation impinging at the top of the atmosphere as a result of the long term evolution of the geomagnetic field. We present preliminary results of an on-going study of geomagnetic cutoff rigidities over a 400-year interval. These results show (1) the change in cutoff rigidity is sufficient large so that the change in cosmic radiation flux impacting the earth is approximately equal to the relative change in flux over a solar cycle, and (2) the changes in cutoff rigidity are non- uniform over the globe with both significant increases and decreases at mid-latitude locations.

Shea, M.; Smart, D.

402

Cosmic Ray Albedo Proton Yield Correlated with Lunar Elemental Abundances  

NASA Astrophysics Data System (ADS)

High energy cosmic rays constantly bombard the lunar regolith, producing secondary "albedo" or "splash" particles like protons and neutrons, some of which escape back to space. Two lunar missions, Lunar Prospector and the Lunar Reconnaissance Orbiter (LRO), have shown that the energy distribution of albedo neutrons is modulated by the elemental composition of the lunar regolith[1-4], with reduced neutron fluxes near the lunar poles being the result of collisions with hydrogen nuclei in ice deposits[5] in permanently shadowed craters. Here we investigate an analogous phenomenon with high energy (~100 MeV) lunar albedo protons. LRO has been observing the surface and environment of the Moon since June of 2009. The CRaTER instrument (Cosmic Ray Telescope for the Effects of Radiation) on LRO is designed to characterize the lunar radiation environment and its effects on simulated human tissue. CRaTER's multiple solid-state detectors can discriminate the different elements in the galactic cosmic ray (GCR) population above ~10 MeV/nucleon, and can also distinguish between primary GCR protons arriving from deep space and albedo particles propagating up from the lunar surface. We use albedo protons with energies greater than 60 MeV to construct a cosmic ray albedo proton map of the Moon. The yield of albedo protons is proportional to the rate of lunar proton detections divided by the rate of incoming GCR detections. The map accounts for time variation in the albedo particles driven by time variations in the primary GCR population, thus revealing any true spatial variation of the albedo proton yield. Our current map is a significant improvement over the proof-of-concept map of Wilson et al.[6]. In addition to including twelve more months of CRaTER data here, we use more numerous minimum ionizing GCR protons for normalization, and we make use of all six of CRaTER's detectors to reduce contamination from spurious non-proton events in the data stream. We find find that the flux of lunar albedo protons is correlated with elemental abundances at the lunar surface. In general the yield of albedo protons from the maria is 1.1% ± 0.4% higher than the flux from the highlands. In addition there appear to be localized peaks in the albedo proton yield that are co-located with peaks in trace elemental abundances as measured by the Lunar Prospector Gamma Ray Spectrometer. References: [1] Feldman W. C. et al. (1998) Sci-ence, 281, 1496-1500. [2] Gasnault, O. et al. (2001) GRL, 28, 3797-3800. [3] Maurice, S. et al. (2004) JGR, 109, E07S04. [4] Mitrofanov I. G. et al. (2010) Science, 330, 483-486. [5] Feldman W. C. et al. (1997) JGR, 102, 25565-25574. [6] Wilson, J. K. et al. (2012) JGR, 117, E00H23.

Wilson, J. K.; Spence, H. E.; Case, A. W.; Blake, J. B.; Golightly, M. J.; Kasper, J. C.; Looper, M. D.; Mazur, J. E.; Schwadron, N. A.; Townsend, L. W.; Zeitlin, C. J.

2012-12-01

403

Cosmic ray modulation and turbulent interaction regions near 11 AU  

NASA Technical Reports Server (NTRS)

When Voyager 2 was near 11 AU, the counting rate of nuclei approx 75 MeV/nucleon decreased during the interval from July, 1982 to November, 1982, and it increased thereafter until August, 1983. A decrease in cosmic ray flux was generally associated with the passage of an interaction region in which the magnetic field strength B was higher than that predicted by the spiral field model, B sub p. Several large enhancements in B/B sup p were associated with merged interaction regions which probably resulted from the interaction of two or more distinct flows. During the passage of interaction regions the cosmic ray intensity decreased at a rate proportional to (B/B sup p -1), and during the passage of rarefaction regions (where B/B sup p 1) the cosmic ray intensity increased at a constant rate. The general form of the cosmic ray intensity profile during this approx 13 month minicycle can be described by integrating these relations using the observed B(t). Latitudinal variations of the interaction regions and of the short-term cosmic ray variations were identified.

Burlaga, L. F.; Mcdonald, F. B.; Goldstein, M. L.; Lazarus, A. J.

1985-01-01

404

Cosmic ray modulation and turbulent interaction regions near 11 AU  

NASA Technical Reports Server (NTRS)

When Voyager 2 was near 11 AU, the counting rate of nuclei approx 75 MeV/nucleon decreased during the interval from July, 1982 to November, 1982, and it increased thereafter until August, 1983. A decrease in cosmic ray flux was generally associated with the passage of an interaction region in which the magnetic field strength B was higher than that predicted by the spiral field model, B sub p. Several large enhancements in B/B sup p were associated with merged interaction regions which probably resulted from the interaction of two or more distinct flows. During the passage of interaction regions the cosmic ray intensity decreased at a rate proportional to (B/B sup p -1), and during the passage of rarefaction regions (where B/B sup p 1) the cosmic ray intensity increased at a constant rate. The general form of the cosmic ray intensity profile during this approx 13 month minicycle can be described by integrating these relations using the observed B(+). Latitudinal variations of the interaction regions and of the short-term cosmic ray variations were identified.

Burlaga, L. F.; Goldstein, M. L.; Mcdonald, F. B.; Lazarus, A. J.

1985-01-01

405

Ineffectiveness of Narrow CMEs for Cosmic Ray Modulation  

NASA Astrophysics Data System (ADS)

Monthly coronal mass ejection (CME) counts, - for all CMEs and CMEs with widths > 30?, - and monthly averaged speeds for the events in these two groups were compared with both the monthly averaged cosmic ray intensity and the monthly sunspot number. The monthly P i-index, which is a linear combination of monthly CME count rate and average speed, was also compared with the cosmic ray intensity and sunspot number. The main finding is that narrow CMEs, which were numerous during 2007 - 2009, are ineffective for modulation. A cross-correlation analysis, calculating both the Pearson ( r) product-moment correlation coefficient and the Spearman ( ?) rank correlation coefficient, has been used. Between all CMEs and cosmic ray intensity we found correlation coefficients r=- 0.49 and ?=- 0.46, while between CMEs with widths > 30? and cosmic ray intensity we found r=- 0.75 and ?=- 0.77, which implies a significant increase. Finally, the best expression for the P i-index for the examined period was analyzed. The highly anticorrelated behavior among this CME index, the cosmic ray intensity ( r=- 0.84 and ?=- 0.83), and the sunspot number ( r=+ 0.82 and ?=+ 0.89) suggests that the first one is a very useful solar-heliospheric parameter for heliospheric and space weather models in general.

Paouris, Evangelos

2013-06-01

406

Estimates of galactic cosmic ray shielding requirements during solar minimum  

NASA Technical Reports Server (NTRS)

Estimates of radiation risk from galactic cosmic rays are presented for manned interplanetary missions. The calculations use the Naval Research Laboratory cosmic ray spectrum model as input into the Langley Research Center galactic cosmic ray transport code. This transport code, which transports both heavy ions and nucleons, can be used with any number of layers of target material, consisting of up to five different arbitrary constituents per layer. Calculated galactic cosmic ray fluxes, dose and dose equivalents behind various thicknesses of aluminum, water and liquid hydrogen shielding are presented for the solar minimum period. Estimates of risk to the skin and the blood-forming organs (BFO) are made using 0-cm and 5-cm depth dose/dose equivalent values, respectively, for water. These results indicate that at least 3.5 g/sq cm (3.5 cm) of water, or 6.5 g/sq cm (2.4 cm) of aluminum, or 1.0 g/sq cm (14 cm) of liquid hydrogen shielding is required to reduce the annual exposure below the currently recommended BFO limit of 0.5 Sv. Because of large uncertainties in fragmentation parameters and the input cosmic ray spectrum, these exposure estimates may be uncertain by as much as a factor of 2 or more. The effects of these potential exposure uncertainties or shield thickness requirements are analyzed.

Townsend, Lawrence W.; Nealy, John E.; Wilson, John W.; Simonsen, Lisa C.

1990-01-01

407

Solar influences on cosmic rays and cloud formation: A reassessment  

NASA Astrophysics Data System (ADS)

Svensmark and Friis-Christensen [1997] proposed a ``cosmic ray-cloud cover'' hypothesis that cosmic ray flux, modulated by solar activity, may modify global cloud cover and thus global surface temperature by increasing the number of ions in the atmosphere, leading to enhanced condensation of water vapor and cloud droplet formation. We evaluate this idea by extending their period of study and examining long-term surface-based cloud data (from national weather services and the Global Telecommunication System) as well as newer satellite data (International Satellite Cloud Climatology Project (ISCCP) D2, 1983-1993). No meaningful relationship is found between cosmic ray intensity and cloud cover over tropical and extratropical land areas back to the 1950s. The high cosmic ray-cloud cover correlation in the period 1983-1991 over the Atlantic Ocean, the only large ocean area over which the correlation is statistically significant, is greatly weakened when the extended satellite data set (1983-1993) is used. Cloud cover data from ship observations over the North Atlantic, where measurements are denser, did not show any relationship with solar activity over the period 1953-1995, though a large discrepancy exists between ISCCP D2 data and surface marine observations. Our analysis also suggests that there is not a solid relationship between cosmic ray flux and low cloudiness as proposed by Marsh and Svensmark [2000].

Sun, Bomin; Bradley, Raymond S.

2002-07-01

408

Cosmic rays flux and geomagnetic field variations at midlatitudes  

NASA Astrophysics Data System (ADS)

It is well known that the cosmic rays flux is modulated by the solar wind and the Earth's magnetic field. The Earth's magnetic field deflects charged particles in accordance with their momentum and the local field strength and direction. The geomagnetic cutoffs depend both on the internal and the external components of the geomagnetic field, therefore reflecting the geodynamo and the solar activity variations. A new generation, high performance, cosmic ray detector Tragaldabas was recently installed at the University of Santiago de Compostela (Spain). The detector has been acquiring test data since September 2013 with a rate of about 80 events/s over a solid angle of ~5 srad. around the vertical direction. To take full advantage of this new facility for the study of cosmic rays arriving to the Earth, an international collaboration has been organized, of about 20 researchers from 10 laboratories of 5 European countries. The Magnetic Observatory of Coimbra (Portugal) has been measuring the geomagnetic field components for almost 150 years since the first measurements in 1866. It is presently equipped with up-to-date instruments. Here we present a preliminary analysis of the global cosmic ray fluxes acquired by the new Tragaldabas detector in relation to the geomagnetic field variations measured by the Coimbra observatory. We also compare the data from the new cosmic rays detector with results obtained by the Castilla-La Mancha Neutron Monitor (CaLMa, Gadalajara, Spain) that is in operation since October 2011.

Morozova, Anna; Ribeiro, Paulo; Tragaldabas collaboration Team

2014-05-01

409

Isotropic Gamma-Ray Background: Cosmic-Ray-Induced Albedo from Debris in the Solar System?  

Microsoft Academic Search

We calculate the gamma-ray albedo due to cosmic-ray interactions with debris (small rocks, dust, and grains) in the Oort Cloud. We show that under reasonable assumptions a significant proportion of what is called the \\

Igor V. Moskalenko; Troy A. Porter

2009-01-01

410

Detection of gamma rays from a starburst galaxy.  

PubMed

Starburst galaxies exhibit in their central regions a highly increased rate of supernovae, the remnants of which are thought to accelerate energetic cosmic rays up to energies of approximately 10(15) electron volts. We report the detection of gamma rays--tracers of such cosmic rays--from the starburst galaxy NGC 253 using the High Energy Stereoscopic System (H.E.S.S.) array of imaging atmospheric Cherenkov telescopes. The gamma-ray flux above 220 billion electron volts is F = (5.5 +/- 1.0(stat) +/- 2.8(sys)) x 10(-13) cm(-2) s(-1), implying a cosmic-ray density about three orders of magnitude larger than that in the center of the Milky Way. The fraction of cosmic-ray energy channeled into gamma rays in this starburst environment is five times as large as that in our Galaxy. PMID:19779150

Acero, F; Aharonian, F; Akhperjanian, A G; Anton, G; Barres de Almeida, U; Bazer-Bachi, A R; Becherini, Y; Behera, B; Bernlöhr, K; Bochow, A; Boisson, C; Bolmont, J; Borrel, V; Brucker, J; Brun, F; Brun, P; Bühler, R; Bulik, T; Büsching, I; Boutelier, T; Chadwick, P M; Charbonnier, A; Chaves, R C G; Cheesebrough, A; Chounet, L-M; Clapson, A C; Coignet, G; Dalton, M; Daniel, M K; Davids, I D; Degrange, B; Deil, C; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubois, F; Dubus, G; Dyks, J; Dyrda, M; Egberts, K; Emmanoulopoulos, D; Espigat, P; Farnier, C; Fegan, S; Feinstein, F; Fiasson, A; Förster, A; Fontaine, G; Füssling, M; Gabici, S; Gallant, Y A; Gérard, L; Gerbig, D; Giebels, B; Glicenstein, J F; Glück, B; Goret, P; Göring, D; Hauser, D; Hauser, M; Heinz, S; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Hofverberg, P; Hoppe, S; Horns, D; Jacholkowska, A; de Jager, O C; Jahn, C; Jung, I; Katarzy?ski, K; Katz, U; Kaufmann, S; Kerschhaggl, M; Khangulyan, D; Khélifi, B; Keogh, D; Klochkov, D; Klu?niak, W; Kneiske, T; Komin, Nu; Kosack, K; Kossakowski, R; Lamanna, G; Lenain, J-P; Lohse, T; Marandon, V; Martineau-Huynh, O; Marcowith, A; Masbou, J; Maurin, D; McComb, T J L; Medina, M C; Méhault, J; Moderski, R; Moulin, E; Naumann-Godo, M; de Naurois, M; Nedbal, D; Nekrassov, D; Nicholas, B; Niemiec, J; Nolan, S J; Ohm, S; Olive, J-F; de Oña Wilhelmi, E; Orford, K J; Ostrowski, M; Panter, M; Paz Arribas, M; Pedaletti, G; Pelletier, G; Petrucci, P-O; Pita, S; Pühlhofer, G; Punch, M; Quirrenbach, A; Raubenheimer, B C; Raue, M; Rayner, S M; Reimer, O; Renaud, M; Rieger, F; Ripken, J; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Ruppel, J; Sahakian, V; Santangelo, A; Schlickeiser, R; Schöck, F M; Schwanke, U; Schwarzburg, S; Schwemmer, S; Shalchi, A; Sikora, M; Skilton, J L; Sol, H; Stawarz, ?; Steenkamp, R; Stegmann, C; Stinzing, F; Superina, G; Szostek, A; Tam, P H; Tavernet, J-P; Terrier, R; Tibolla, O; Tluczykont, M; van Eldik, C; Vasileiadis, G; Venter, C; Venter, L; Vialle, J P; Vincent, P; Vivier, M; Völk, H J; Volpe, F; Wagner, S J; Ward, M; Zdziarski, A A; Zech, A

2009-11-20

411

Electron Heating, Magnetic Field Amplification, and Cosmic-Ray Precursor Length at Supernova Remnant Shocks  

NASA Astrophysics Data System (ADS)

We investigate the observability, by direct and indirect means, of a shock precursor arising from magnetic field amplification by cosmic rays. We estimate the depth of such a precursor under conditions of nonresonant amplification, which can provide magnetic field strengths comparable to those inferred for supernova remnants. Magnetic field generation occurs as the streaming cosmic rays induce a plasma return current, and it may be quenched by either nonresonant or resonant channels. In the case of nonresonant saturation, the cosmic rays become magnetized and amplification saturates at higher magnetic fields. The precursor can extend out to 1017-1018 cm and is potentially detectable. If resonant saturation occurs, the cosmic rays are scattered by turbulence and the precursor length will likely be much smaller. The dependence of precursor length on shock velocity has implications for electron heating. In the case of resonant saturation, this dependence is similar to that in the more familiar resonantly generated shock precursor, which when expressed in terms of the cosmic-ray diffusion coefficient kappav and shock velocity vs is kappav/vs . In the nonresonantly saturated case, the precursor length declines less quickly with increasing vs . Where precursor length proportional to 1/vs gives constant electron heating, this increased precursor length could be expected to lead to higher electron temperatures for nonresonant amplification. This should be expected at faster supernova remnant shocks than studied by previous works. Existing results and new data analysis of SN 1006 and Cas A suggest some observational support for this idea.

Laming, J. Martin; Hwang, Una; Ghavamian, Parviz; Rakowski, Cara

2014-07-01

412

Cosmic-ray induced gamma-ray emission from the starburst galaxy NGC 253  

NASA Astrophysics Data System (ADS)

Cosmic rays in galaxies interact with the interstellar medium and give us a direct view of nuclear and particle interactions in the cosmos. For example, cosmic-ray proton interactions with interstellar hydrogen produce gamma rays via PcrPism??0???. For a "normal" star-forming galaxy like the Milky Way, most cosmic rays escape the Galaxy before such collisions, but in starburst galaxies with dense gas and huge star formation rate, most cosmic rays do suffer these interactions [1,2]. We construct a "thick-target" model for starburst galaxies, in which cosmic rays are accelerated by supernovae, and escape is neglected. This model gives an upper limit to the gamma-ray emission. Only two free parameters are involved in the model: cosmic-ray proton acceleration energy rate from supernova and the proton injection spectral index. The pionic gamma-radiation is calculated from 10 MeV to 10 TeV for the starburst galaxy NGC 253, and compared to Fermi and HESS data. Our model fits NGC 253 well, suggesting that cosmic rays in this starburst are in the thick target limit, and that this galaxy is a gamma-ray calorimeter.

Wang, Xilu; Fields, Brian D.

2014-05-01

413

Measuring 10-1000 GeV Cosmic Ray Electrons with GLAST/LAT.  

National Technical Information Service (NTIS)

We present here the capabilities of the GLAST Large Area Telescope to detect cosmic ray high-energy (HE) electrons in the energy range from 10 GeV to 1 TeV. We also discuss the science topics that can be investigated with HE electron data and quantify the...

A. A. Moiseev I. V. Moskalenko J. F. Ormes

2007-01-01

414

The origin of Galactic Cosmic Rays: theory confronts observations  

NASA Astrophysics Data System (ADS)

This year, the world celebrates the centennial of the discovery of Cosmic Radiation by the austrian-american physicist Victor Hess. With his balloon flights, Hess provided an answer to a major mystery of the times, proving that the anomalous radiation measured by electroscopes came from the sky rather than from some unknown radioactive source on Earth. This Nobel Prize worth discovery, quickly followed up by the finding that the cosmic radiation consisted of highly energetic particles, started the quest for the astrophysical sources of cosmic rays and for the physical processes behind their acceleration. Cosmic ray physics has been a very active field of research, attracting the attention of some of the most brilliant minds of the century. While the measured cosmic ray spectrum extends up to energies exceeding a billion TeV (namely a billion times the energy of collisions at LHC) this talk will focus on particles up to PeV energies. These are thought to be of Galactic origin and a long standing paradigm assumes them to be accelerated in Supernova Remnants by the process of ``Diffusive Shock Acceleration.'' This paradigm has been eluding definite proof for many decades and only recently the combination of theoretical and experimental progress has become such as to finally prove or disprove it. I will review recent theoretical progress on the subject of particle acceleration at Supernova Remnant shocks and of cosmic ray propagation in the Galaxy. I will then discuss how theory compares with observations and the current challenges to existing paradigms on the origin and propagation of Galactic Cosmic Rays.

Amato, Elena

2012-03-01

415

Supernova Remnants Interacting with Molecular Clouds:. a New way to Reveal Cosmic Rays  

NASA Astrophysics Data System (ADS)

Molecular clouds interact with the ambient cosmic rays. The decay of secondary particles may give rise to a detectable flux of very high-energy photons. Recently the H.E.S.S., MAGIC and VERITAS telescopes have observed such sources associated with large molecular clouds and shell-type supernova remnants. Emission lines of OH masers are also observed in coincidence. This ensures that the expanding wave front of the supernova interacts effectively with the cloud. Such natural configurations bring new material to confront with the hypothesis that supernova remnants are the Galactic cosmic-ray accelerators. We describe the approach towards a systematic observation of such associations, present the current data and review the prospects of these studies for answering the question of the origin of the Galactic cosmic rays.

Feinstein, F.; Fiasson, A.

2011-03-01

416

On the effect of cosmic rays in bolometric cosmic microwave background measurements from the stratosphere  

NASA Astrophysics Data System (ADS)

Context. Precision measurements of the anisotropy of the cosmic microwave background (CMB) are able to detect low-level non-Gaussian features caused by either topological defects or the inflation process. These measurements are becoming feasable with the development of large arrays of ultra-sensitive bolometric detectors and their use in balloon-borne or satellite missions. However, the space environment includes a population of cosmic rays (CRs), which produce spurious spikes in bolometric signals. Aims: We analyze the effect of CRs on the measurement of CMB anisotropy maps and the estimate of cosmological non-Gaussianity and angular power spectra of the CMB. Methods: Using accurate simulations of noise and CR events in bolometric detectors, and de-spiking techniques, we produce simulated measured maps and analyze the Gaussianity and power spectrum of the maps for different levels and rates of CR events. Results: We find that a de-spiking technique based on outlier removal in the detector signals contributing to the same sky pixel is effective in removing CR events larger than the noise. However, low level events hidden in the noise produce a positive shift of the average power signal measured by a bolometer, and increase its variance. If the number of hits per pixel is large enough, the data distribution for each sky pixel is approximately Gaussian, but the skewness and the kurtosis of the temperatures of the pixels indicate the presence of some low-level non-Gaussianity. The standard noise estimation pipeline produces a positive bias in the power spectrum at high multipoles. Conclusions: In the case of a typical balloon-borne survey, the CR-induced non-Gaussianity will be marginally detectable in the membrane bolometer channels, but be negligible in the spider-web bolometer channels. In experiments with detector sensitivity better than 100 ?K/?{Hz}, in an environment less favorable than the earth stratosphere, the CR-induced non-Gaussianity is likely to significantly affect the results.

Masi, S.; Battistelli, E.; de Bernardis, P.; Lamagna, L.; Nati, F.; Nati, L.; Natoli, P.; Polenta, G.; Schillaci, A.

2010-09-01

417

Cosmic rays and terrestrial life: A brief review  

NASA Astrophysics Data System (ADS)

“The investigation into the possible effects of cosmic rays on living organisms will also offer great interest.” - Victor F. Hess, Nobel Lecture, December 12, 1936 High-energy radiation bursts are commonplace in our Universe. From nearby solar flares to distant gamma ray bursts, a variety of physical processes accelerate charged particles to a wide range of energies, which subsequently reach the Earth. Such particles contribute to a number of physical processes occurring in the Earth system. A large fraction of the energy of charged particles gets deposited in the atmosphere, ionizing it, causing changes in its chemistry and affecting the global electric circuit. Remaining secondary particles contribute to the background dose of cosmic rays on the surface and parts of the subsurface region. Life has evolved over the past ?3 billion years in presence of this background radiation, which itself has varied considerably during the period [1-3]. As demonstrated by the Miller-Urey experiment, lightning plays a very important role in the formation of complex organic molecules, which are the building blocks of more complex structures forming life. There is growing evidence of increase in the lightning rate with increasing flux of charged particles. Is there a connection between enhanced rate of cosmic rays and the origin of life? Cosmic ray secondaries are also known to damage DNA and cause mutations, leading to cancer and other diseases. It is now possible to compute radiation doses from secondary particles, in particular muons and neutrons. Have the variations in cosmic ray flux affected the evolution of life on earth? We describe the mechanisms of cosmic rays affecting terrestrial life and review the potential implications of the variation of high-energy astrophysical radiation on the history of life on earth.

Atri, Dimitra; Melott, Adrian L.

2014-01-01

418

A cosmic gamma-ray burst on May 14, 1975  

NASA Technical Reports Server (NTRS)

A cosmic gamma-ray burst is reported that occurred at 29309.11 s UTC, May 14, 1975. The burst was detected at an atmospheric depth of 4 g/sq cm residual atmosphere with the University of California double scatter gamma-ray telescope launched on a balloon from Palestine, Texas at 1150 UTC, May 13, 1975. The burst was observed both in the single scatter mode by the top liquid scintillator tank in anti-coincidence with the surrounding plastic scintillator and in the double scatter mode from which energy and directional information are obtained. The burst is 24 standard deviations above the background for single scatter events. The total gamma-ray flux in the burst, incident on the atmosphere with photon energy greater than 0.5 MeV, is 0.59 + or - 0.15 photons/sq cm. The initial rise time to 90% of maximum is 0.015 + or - 0.005 s and the duration is 0.11 s. Time structure down to the 5 ms resolution of the telescope is seen. The mean flux over this time period is 5.0 + or - 1.3 photons/sq cm/s and the maximum flux is 8.5 + or - 2.1 photons/sq cm/s.

Herzo, D.; Dayton, B.; Zych, A. D.; White, R. S.

1975-01-01

419

Quantifying mesoscale soil moisture with the cosmic-ray rover  

NASA Astrophysics Data System (ADS)

Existing techniques measure soil moisture either at a point or over a large area many kilometers across. To bridge these two scales, we used the mobile cosmic-ray probe, or cosmic-ray rover, an instrument similar to the recently developed COSMOS probe, but bigger and mobile. This study explores the challenges and opportunities for making maps of soil moisture over large areas using the cosmic-ray rover. In 2012, soil moisture was mapped 22 times in a 25 km x 40 km survey area of the Tucson Basin at 1 km 2 resolution, i.e., at a scale comparable to that of a pixel for the Soil Moisture and Ocean Salinity (SMOS) satellite mission. The soil moisture distribution is influenced mainly by climatic variations, notably by the North American monsoon, which resulted in a systematic change in the regional variance as a function of the mean soil moisture.

Chrisman, Bobby B.

420

Origin of the Cosmic-Ray Spectral Hardening  

NASA Astrophysics Data System (ADS)

Recent data from ATIC, CREAM, and PAMELA indicate that the cosmic-ray energy spectra of protons and nuclei exhibit a remarkable hardening at energies above 100 GeV nucleon-1. We propose that the hardening is an interstellar propagation effect that originates from a spatial change of the cosmic-ray transport properties in different regions of the Galaxy. The key hypothesis is that the diffusion coefficient is not separable into energy and space variables as usually assumed. Under this scenario, we can reproduce the observational data well. Our model has several implications for cosmic-ray acceleration/propagation physics and can be tested by ongoing experiments such as the Alpha Magnetic Spectrometer or Fermi-LAT.

Tomassetti, Nicola

2012-06-01

421

A Cosmic-Ray Resolution to the Superbubble Energy Crisis  

NASA Astrophysics Data System (ADS)

Superbubbles (SBs) are among the greatest injectors of energy into the Galaxy, and have been proposed to be the acceleration site of Galactic cosmic rays. They are thought to be powered by the fast stellar winds and powerful supernova explosions of massive stars in dense stellar clusters and associations. Observations of the SB ``DEM L192'' in the neighboring Large Magellanic Cloud (LMC) show that it contains only about one-third the energy injected by its constituent stars via fast stellar winds and supernovae. It is not yet understood where the excess energy is going-thus, the so-called energy-crisis. We show here that it is very likely that a significant fraction of the unaccounted for energy is being taken up in accelerating cosmic rays, thus bolstering the argument for the SB origin of cosmic rays.

Butt, Yousaf M.; Bykov, Andrei M.

2008-04-01

422

Opportunities in cosmic-ray physics and astrophysics  

NASA Technical Reports Server (NTRS)

The Board on Physics and Astronomy of the National Research Council established the Committee on Cosmic-Ray Physics to prepare a review of the field that addresses both experimental and theoretical aspects of the origin of cosmic radiation from outside the heliosphere. The following recommendations are made: NASA should provide the opportunity to measure cosmic-ray electrons, positrons, ultraheavy nuclei, isotopes, and antiparticles in space; NASA, the National Science Foundation (NSF), and the Department of Energy (DOE) should facilitate direct and indirect measurement of the elemental composition to as high an energy as possible, for which the support of long-duration ballooning and hybrid ground arrays will be needed; NSF and DOE should support the new Fly's Eye and provide for U.S. participation in the big projects on the horizon, which include giant arrays, ground-based gamma-ray astronomy, and neutrino telescopes; and NASA, NSF, and DOE should support a strong program of relevant theoretical investigations.

1995-01-01

423