1. |
- Munini, R., et al.
(author)
-
Solar modulation of galactic cosmic rays electrons and positrons over the 23rd solar minimum with the pamela experiment
- 2013
-
In: Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013. - : Sociedade Brasileira de Fisica. - 9788589064293
-
Conference paper (peer-reviewed)abstract
- The satellite-borne PAMELA experiment has been continuously collecting data since 15th June 2006, when it was launched from the Baikonur cosmodrome to detect the charged component of cosmic rays over a wide energy range and with an unprecedented statistics. The apparatus design is particularly suited for particle and antiparticle identification. The satellite quasi-polar orbit, with an inclination of 70 degrees, allows particles to be measure down to 100 MeV/n. This makes the instrument suited for the investigation of phenomena related to galactic cosmic ray solar modulation in the inner heliosphere. Data for oppositely charged particles were collected from 2006 to 2009, during the A< 0 solar minimum of solar cycle 23. The time and rigidity dependence of galactic cosmic ray electron and positron fluxes were measured. These fluxes provide important information for the study of charge dependent solar modulation effects.
|
|
2. |
- Carbone, R., et al.
(author)
-
Pamela observation of the 2012 may 17 gle event
- 2013
-
In: Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013. - : Sociedade Brasileira de Fisica. - 9788589064293
-
Conference paper (peer-reviewed)abstract
- The PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) satellite-borne experiment has been collecting data in orbit since July 2006, providing accurate measurements of the energy spectra and composition of the cosmic radiation from a few hundred MeV/n up to hundred GeV/n. This wide interval of measured energies makes PAMELA a unique instrument for Solar Energetic Particle (SEP) observations. Not only does it span the energy range between the ground-based neutron monitor data and the observations of SEPs from space, but also PAMELA carries out the first direct measurements of the composition for the highest energy SEP events, including those causing Ground Level Enhancements (GLEs). PAMELA has registered many SEP events in solar cycle 24 including the 2012 May 17 GLE event (GLE 71), offering unique opportunities to address the question of high-energy SEP origin. Experimental performances and preliminary results on the 2012 May 17 events will be presented. We will discuss the derived particle injection time and compare with other time scales at the Sun including the flare and CME onset times.
|
|
3. |
- Di Felice, V., et al.
(author)
-
Solar modulation of galactic hydrogen and helium over the 23rd solar minimum with the PAMELA experiment
- 2013
-
In: Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013. - : Sociedade Brasileira de Fisica. - 9788589064293
-
Conference paper (peer-reviewed)abstract
- PAMELA has been orbiting the Earth for more than six years, gathering data on solar, galactic and trapped cosmic rays during the time of the last solar minimum. The apparatus comprises a time-of-flight system, a silicon-microstrip magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anticoincidence system, a shower tail catcher scintillator and a neutron detector. The combination of these devices allows charged particle and antiparticle identification over a wide energy range and with an unprecedented precision. The quasi-polar orbit of the instrument, with an inclination of 70 degrees, makes it possible to measure low energy particles starting from about 100 MeV/n. In this work we present the time and rigidity dependence of the galactic proton and helium fluxes over the first 4 years of operation during the A < 0 solar minimum of solar cycle 23.
|
|
4. |
- Mocchiutti, E., et al.
(author)
-
Cosmic–ray positron energy spectrum measured by PAMELA
- 2013
-
In: Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013. - : Sociedade Brasileira de Fisica. - 9788589064293
-
Conference paper (peer-reviewed)abstract
- The PAMELA satellite borne experiment is designed to study cosmic rays with great accuracy in a wide energy range. One of PAMELA’s main goal is the study of the antimatter component of cosmic rays. The experiment, housed on board the Russian satellite Resurs–DK1, was launched on June 15th 2006 and it is still taking data. In this work we present the measurement of galactic positron energy spectrum in the energy range between 500 MeV and few hundred GeV.
|
|
5. |
- Ricci, M., et al.
(author)
-
Study on 2012 march 7 solar particle event and forbush decrease with the PAMELA experiment
- 2013
-
In: Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013. - : Sociedade Brasileira de Fisica. - 9788589064293
-
Conference paper (peer-reviewed)abstract
- The PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astro-physics) space-borne experiment was launched on 15 June 2006 and has been continuously collecting data since then. The apparatus measures electrons, positrons, protons, anti-protons and heavier nuclei from about 100 MeV to several hundreds of GeV. The on-board instrumentation is built around a permanent magnet with a silicon microstrip tracker, providing charge and track detection information. During solar maximum conditions of solar cycle 24, PAMELA has been providing key information about solar energetic particles (SEPs) and their influence at Earth. We discuss here the recent 2012 March 7 SEP event with a brief comment on the subsequent Forbush decrease, registered by PAMELA. This event was also observed by Fermi/LAT exhibiting unprecedented time-extended γ-ray emission (> 100 MeV) lasting nearly 20 hours. We compare the derived accelerated ion population at the Sun with the ion population measured in space by PAMELA and discuss the implications for particle acceleration.
|
|
6. |
- Topchiev, N. P., et al.
(author)
-
GAMMA-400 gamma-ray observatory
- 2015
-
In: Proceedings of Science. - : Proceedings of Science (PoS).
-
Conference paper (peer-reviewed)abstract
- The GAMMA-400 gamma-ray telescope with excellent angular and energy resolutions is designed to search for signatures of dark matter in the fluxes of gamma-ray emission and electrons+ positrons.Precision investigations of gamma-ray emission fromGalactic Center, Crab, Vela, Cygnus, Geminga, and other regions will be performed, as well asdiffuse gamma-rayemission,along with measurements of high-energy electron + positron and nuclei fluxes. Furthermore, it will studygamma-ray bursts and gamma-ray emission from the Sun during periods of solar activity. The energy range of GAMMA-400 is expected to be from ∼20 MeV up to TeV energies for gamma rays, up to 10 TeV for electrons + positrons, and up to 1015eV for cosmic-ray nuclei. For high-energy gamma rays with energy from 10 to 100 GeV, the GAMMA-400 angular resolution improves from 0.1° to ∼0.01° and energy resolution from 3% to ∼1%; the proton rejection factor is ∼5x105. GAMMA-400 will be installed onboardthe Russian space observatory.
|
|
7. |
- Adriani, O., et al.
(author)
-
The gamma-400 space observatory : Status and perspectives
- 2014
-
In: Proceedings of Science. - : Sissa Medialab Srl.
-
Conference paper (peer-reviewed)abstract
- The present design of the new space observatory GAMMA-400 is presented in this paper. The instrument has been designed for the optimal detection of gamma rays in a broad energy range (from ∼100 MeV up to 3 TeV), with excellent angular and energy resolution. The observatory will also allow precise and high statistic studies of the electron component in the cosmic rays up to the multi TeV region, as well as protons and nuclei spectra up to the knee region. The GAMMA-400 observatory will allow to address a broad range of science topics, like search for signatures of dark matter, studies of Galactic and extragalactic gamma-ray sources, Galactic and extragalactic diffuse emission, gamma-ray bursts and charged cosmic rays acceleration and diffusion mechanism up to the knee.
|
|
8. |
- Casolino, M., et al.
(author)
-
New upper limit on strange quark matter flux with the PAMELA experiment
- 2013
-
In: Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013. - : Sociedade Brasileira de Fisica. - 9788589064293
-
Conference paper (peer-reviewed)abstract
- In this work we present a new upper limit for anomalous charge / mass (Z/A) particles with PAMELA experiment. These particles would exhibit a low velocity in the Time-of-Flight system and an high rigidity in the tracker. The redundant nature of the PAMELA detectors make it particularly suited to search for these particles in a mass number (10 ≤ A ≤ 105), charge (1≤ Z ≤ 8) and rigidity (0.4 ≤ R ≤ 1200 GV) range complementary to those of ground-based experiments.
|
|
9. |
- Formato, V., et al.
(author)
-
Hydrogen and helium isotopes flux in cosmic rays with the PAMELA experiment
- 2013
-
In: Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013. - : Sociedade Brasileira de Fisica. - 9788589064293
-
Conference paper (peer-reviewed)abstract
- PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature, with particular focus on the antimatter component. The detector consists of a permanent magnet spectrometer core to provide rigidity and charge sign information, a Time-of-Flight system for velocity and charge information, a Silicon-Tungsten calorimeter and a Neutron detector for lepton/hadron identification. The beta and rigidity information allow to identify isotopes for Z = 1 and Z = 2 particles in the energy range 100 MeV/n to 1 GeV/n. In this work we will present the final PAMELA results on the H and He isotope fluxes measured during the 23rd solar minimum from 2006 to 2007. Such fluxes carry relevant information helpful in constraining parameters in galactic cosmic rays propagation models complementary to those obtained from other secondary to primary measurements such as the boron-to-carbon ratio.
|
|
10. |
- Leonov, A. A., et al.
(author)
-
Separation of electrons and protons in the GAMMA-400 gamma-ray telescope
- 2015
-
In: Advances in Space Research. - : Elsevier BV. - 0273-1177 .- 1879-1948. ; 56:7, s. 1538-1545
-
Journal article (peer-reviewed)abstract
- The GAMMA-400 telescope will measure the fluxes of gamma rays and cosmic-ray electrons and positrons in the energy range from 100 MeV to several TeV. These measurements will allow it to achieve the following scientific objectives: search for signatures of dark matter, investigation of gamma-ray point-like and extended sources, study of the energy spectrum of the Galactic and extragalactic diffuse emission, study of gamma-ray bursts and gamma-ray emission from the active Sun, together with high-precision measurements of the high-energy electrons and positrons spectra, protons and nuclei up to the knee. The bulk of cosmic rays are protons and helium nuclei, whereas the lepton component in the total flux is similar to 10(-3) at high energy. In the present paper, the simulated capability of the GAMMA-400 telescope to distinguish electrons and positrons from protons in cosmic rays is addressed. The individual contribution to the proton rejection from each detector system of GAMMA-400 is studied separately. The use of the combined information from all detectors allows us to reach a proton rejection of the order of similar to 4 x 10(5) for vertical incident particles and similar to 3 x 10(5) for particles with initial inclination of 30 degrees in the electron energy range from 50 GeV to 1 TeV. (C) 2015 COSPAR.
|
|
11. |
- Leonov, A. A., et al.
(author)
-
The GAMMA-400 gamma-ray telescope characteristics. Angular resolution and electrons/protons separation
- 2014
-
In: Proceedings of Science. - : Sissa Medialab Srl.
-
Conference paper (peer-reviewed)abstract
- The measurements of gamma-ray fluxes and cosmic-ray electrons and positrons in the energy range from 100 MeV to several TeV, which will be realized by the specially designed GAMMA-400 gamma-ray telescope, concern with the following broad range of scientific topics. Search for signatures of dark matter, surveying the celestial sphere in order to study point and extended sources of gamma-rays, measuring the energy spectra of Galactic and extragalactic diffuse gamma-ray emission, study of gamma-ray bursts and gamma-ray emission from the Sun, as well as high precision measurements of spectra of high-energy electrons and positrons, protons and nuclei up to the knee. To clarify these scientific problems with the new experimental data the GAMMA-400 gamma-ray telescope possesses unique physical characteristics comparing with previous and present experiments. For gamma-ray energies more than 100 GeV GAMMA-400 provides the energy resolution ~1% and angular resolution better than 0.02 deg. The methods, developed to reconstruct the direction of incident gamma photon, are presented in this paper, as well as, the capability of the GAMMA-400 gamma-ray telescope to distinguish electrons and positrons from protons in cosmic rays is investigated. The first point concerns with the space topology of high-energy gamma photon interaction in the matter of GAMMA-400. Multiple secondary particles, generated inside gamma-ray telescope, produce significant problems to restore the direction of initial gamma photon. Also back-splash particles, i.e., charged particles and gamma photons generated in calorimeter and moved upward, mask the initial tracks of electron/positron pair from conversion of incident gamma photon. The processed methods allow us to reconstruct the direction of electromagnetic shower axis and extract the electron/positron trace. As a result, the direction of incident gamma photon with the energy of 100 GeV is calculated with an accuracy of better than 0.02 deg. The main components of cosmic rays are protons and helium nuclei, whereas the part of lepton component in the total flux is ~10 -3 for high energies. The separate contribution in proton rejection is studied for each detector system of the GAMMA-400 gamma-ray telescope. Using combined information from all detector systems allow us to provide the rejection from protons with a factor of ~4 10 5 for vertical incident particles and ~3 10 5 for particle with initial inclination of 30 deg. Science with the New Generation of High Energy Gamma-ray experiments, 10th Workshop (Scineghe2014) 04-06 June 2014 Lisbon - Portugal.
|
|
12. |
- Merge, M., et al.
(author)
-
Multi-particle analysis of the december 13th 2006 forbush decrease with PAMELA experiment
- 2013
-
In: Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013. - : Sociedade Brasileira de Fisica. - 9788589064293
-
Conference paper (peer-reviewed)abstract
- In this paper we present PAMELA multi-particle observation of the Forbush decrease (FD) following the December 13th 2006 solar particle event. The FD is the sudden decrease of the galactic cosmic ray flux due to the transit of a Coronal Mass Ejection (CME). The satellite-borne experiment PAMELA on-board Resurs-DK1 satellite and consist of a magnetic spectrometer with time-of-flight and calorimeter detectors. PAMELA can study in real time with high precision the temporal and energetic evolution of several particle fluence during and after crossing of the magnetic cloud generated by the CME. The effect is stronger than what detected on ground with neutron monitor. With flux reduction can be as high as 30% decreasing at 1.5GV. No difference of the FD has been found for different particles proving that there is no charge sign dependence of FD for this event.
|
|
13. |
- Topchiev, N. P., et al.
(author)
-
The GAMMA-400 experiment : Status and prospects
- 2015
-
In: Bulletin of the Russian Academy of Sciences: Physics. - 1062-8738. ; 79:3, s. 417-420
-
Journal article (peer-reviewed)abstract
- The development of the GAMMA-400 γ-ray telescope continues. The GAMMA-400 is designed to measure fluxes of γ-rays and the electron-positron cosmic-ray component possibly associated with annihilation or decay of dark matter particles; and to search for and study in detail discrete γ-ray sources, to measure the energy spectra of Galactic and extragalactic diffuse γ-rays, and to study γ-ray bursts and γ-rays from the active Sun. The energy range for measuring γ-rays and electrons (positrons) is from 100 MeV to 3000 GeV. For 100-GeV γ-rays, the γ-ray telescope has an angular resolution of ∼0.01°, an energy resolution of ∼1%, and a proton rejection factor of ∼5 × 105. The GAMMA-400 will be installed onboard the Russian Space Observatory.
|
|
14. |
- Adriani, O., et al.
(author)
-
Antiprotons in primary cosmic radiation with PAMELA experiment
- 2013
-
In: Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013. - : Sociedade Brasileira de Fisica. - 9788589064293
-
Conference paper (peer-reviewed)abstract
- The latest measurements of antiprotons spectrum and antiproton-to-proton ratio in primary cosmic rays with PAMELA experiment are presented. They are in good agreement with model of secondary production of antiprotons in Galaxy, but they do not completely rule other sources at the high-energies.
|
|
15. |
- Adriani, O., et al.
(author)
-
Time Dependence of the Electron and Positron Components of the Cosmic Radiation Measured by the PAMELA Experiment between July 2006 and December 2015
- 2016
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 116:24
-
Journal article (peer-reviewed)abstract
- Cosmic-ray electrons and positrons are a unique probe of the propagation of cosmic rays as well as of the nature and distribution of particle sources in our Galaxy. Recent measurements of these particles are challenging our basic understanding of the mechanisms of production, acceleration, and propagation of cosmic rays. Particularly striking are the differences between the low energy results collected by the space-borne PAMELA and AMS-02 experiments and older measurements pointing to sign-charge dependence of the solar modulation of cosmic-ray spectra. The PAMELA experiment has been measuring the time variation of the positron and electron intensity at Earth from July 2006 to December 2015 covering the period for the minimum of solar cycle 23 (2006-2009) until the middle of the maximum of solar cycle 24, through the polarity reversal of the heliospheric magnetic field which took place between 2013 and 2014. The positron to electron ratio measured in this time period clearly shows a sign-charge dependence of the solar modulation introduced by particle drifts. These results provide the first clear and continuous observation of how drift effects on solar modulation have unfolded with time from solar minimum to solar maximum and their dependence on the particle rigidity and the cyclic polarity of the solar magnetic field.
|
|
16. |
- Adriani, O., et al.
(author)
-
Time Dependence Of The Proton Flux Measured By Pamela During The 2006 July-2009 December Solar Minimum
- 2013
-
In: Astrophysical Journal. - : IOP Publishing. - 0004-637X .- 1538-4357. ; 765:2, s. 91-
-
Journal article (peer-reviewed)abstract
- The energy spectra of galactic cosmic rays carry fundamental information regarding their origin and propagation. These spectra, when measured near Earth, are significantly affected by the solar magnetic field. A comprehensive description of the cosmic radiation must therefore include the transport and modulation of cosmic rays inside the heliosphere. During the end of the last decade, the Sun underwent a peculiarly long quiet phase well suited to study modulation processes. In this paper we present proton spectra measured from 2006 July to 2009 December by PAMELA. The large collected statistics of protons allowed the time variation to be followed on a nearly monthly basis down to 400 MV. Data are compared with a state-of-the-art three-dimensional model of solar modulation.
|
|
17. |
- Formato, V., et al.
(author)
-
Galactic boron and carbon fluxes measured by the PAMELA experiment
- 2013
-
In: Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013. - : Sociedade Brasileira de Fisica. - 9788589064293
-
Conference paper (peer-reviewed)abstract
- The PAMELA experiment is a satellite-borne apparatus that performs measurements of the cosmic radiation with a particular focus on antiparticles and light nuclei. The heart of experiment is a magnetic spectrometer to measure the particle rigidity and sign of charge. A Time-of-Flight system, a Silicon-Tungsten calorimeter, and a neutron detector allow particle identification and lepton/hadron discrimination. The apparatus is surrounded by a set of anticoincidence scintillation counters to reject multi-particle events. In this work we will present the Boron and Carbon fluxes measured by PAMELA from July 2006 to March 2008. Such data, and in particular the B/C flux ratio, can help the modelling of the galactic cosmic rays propagation. This can be a crucial point in predicting the astrophysical background of antimatter (positrons and antiprotons) in cosmic rays in the search for a dark matter signal.
|
|
18. |
- Menn, W., et al.
(author)
-
Lithium and beryllium isotopes in the pamela-experiment
- 2015
-
In: Proceedings of Science. - : Proceedings of Science (PoS).
-
Conference paper (peer-reviewed)abstract
- On the 15th of June 2006, the PAMELA satellite-borne experiment was launched from the Baikonur cosmodrome and it has been collecting data since July 2006. The apparatus comprises a time-of-flight system, a silicon-microstrip magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anti-coincidence system, a shower tail counter scintillator and a neutron detector. The scientific objectives addressed by the mission are the measurement of the antiprotons and positrons spectra in cosmic rays, the hunt for antinuclei as well as the determination of light nuclei fluxes from hydrogen to oxygen in a wide energy range and with very high statistics. In this paper the identification capability for lithium and beryllium isotopes for two different techniques are presented, combining the rigidity measurement from the magnetic spectrometer with the velocity information derived either with the time-of-flight or with multiple dE/dx measurements in the calorimeter. Preliminary results of the isotopic ratios will be presented.
|
|
19. |
- Menn, W., et al.
(author)
-
Measurement of the isotopic composition of hydrogen and helium nuclei in cosmic rays with the pamela-experiment
- 2015
-
In: Proceedings of Science. - : Proceedings of Science (PoS).
-
Conference paper (peer-reviewed)abstract
- The cosmic-ray hydrogen and helium (1H,2H,3He,4He) isotopic composition between 100 MeV/n and 1.4 GeV/n has been measured with the satellite-borne experiment PAMELA, which was launched into low-Earth orbit on-board the Resurs-DK1 satellite on June 15th 2006. The rare isotopes 2H and 3He in cosmic rays are believed to originate mainly from the interaction of high energy protons and helium with the galactic interstellar medium. The energy spectrum of these components carries fundamental information regarding the propagation of cosmic rays in the galaxy which are competitive with those obtained from other secondary to primary measurements such as B/C. The isotopic composition was measured between 100 and 1100 MeV/n for hydrogen and between 100 and 1400 MeV/n for helium isotopes using two different detector systems over the 23rd solar minimum from July 2006 to December 2007.
|
|
20. |
- Munini, R., et al.
(author)
-
Solar modulation of galactic cosmic ray electrons and positrons over the 23rd solar minimum with the PAMELA experiment
- 2015
-
In: Proceedings of Science. - : Proceedings of Science (PoS).
-
Conference paper (peer-reviewed)abstract
- The satellite-borne PAMELA experiment has been continuously collecting data since 15th June 2006, when it was launched from the Baikonur cosmodrome to detect the charged component of cosmic rays over a wide energy range and with unprecedented statistics. The apparatus design is particularly suited for particle and antiparticle identification. The PAMELA experiment has measured the time variation of electron and positron spectrum at Earth in great detail, extending the measurement down to 70 MeV and 200 MeV respectively. The spectra have been evaluated with data collected from July 2006 to December 2009, i.e. during the A<0 solar minimum of solar cycle 23, over six-months intervals. These spectra provide important information for the study of CR propagation inside the heliosphere and the investigation of the charge-dependent solar modulation.
|
|
21. |
- Munini, R., et al.
(author)
-
Solar modulation of GCR electrons over the 23rd solar minimum with PAMELA
- 2015
-
In: 24TH EUROPEAN COSMIC RAY SYMPOSIUM (ECRS). - : IOP Publishing.
-
Conference paper (peer-reviewed)abstract
- The satellite-borne PAMELA experiment has been continuously collecting data since 15th June 2006, when it was launched from the Baikonur cosmodrome to detect the charged component of cosmic rays over a wide energy range and with unprecedented statistics. The apparatus design is particularly suited for particle and antiparticle identification. The PAMELA experiment has measured the electron spectrum at Earth in great detail, extending up to about 100 GeV and down to about 200 MeV. The galactic cosmic ray electron spectra for 2007 and 2009, i.e. measured during the A<0 solar minimum of solar cycle 23, are presented. These fluxes provide important information for the study of charge dependent solar modulation effects.
|
|
22. |
- Vannuccini, E., et al.
(author)
-
Measurement of Lithium and Beryllium cosmic-ray abundances by the PAMELA experiment
- 2015
-
In: Proceedings of Science. - : Proceedings of Science (PoS).
-
Conference paper (peer-reviewed)abstract
- The PAMELA experiment is collecting particles along a low Earth semi-polar orbit on board of Resurs-DK1 satellite since June 2006. The combined information of a silicon tracking system and a scintillator hodoscope provides redundant light-element identification capabilities, via multiple ionization energy-loss measurements. The instrument design is not optimized for nuclei detection, whose high ionization signal progressively saturates the detectors. However, Li and Be nuclei can still be identified by using the full set of information, which allows to efficiently select the two elements against the background of more abundant elements. The main issues of the analysis aiming to optimize the Li and Be selection are discussed in this paper. Preliminary results on the elemental abundances will be presented at the conference.
|
|
23. |
- Adriani, O., et al.
(author)
-
Pamela's measurements of magnetospheric effects on high-energy solar particles
- 2015
-
In: Astrophysical Journal Letters. - 2041-8205 .- 2041-8213. ; 801:1
-
Journal article (peer-reviewed)abstract
- The nature of particle acceleration at the Sun, whether through flare reconnection processes or through shocks driven by coronal mass ejections, is still under scrutiny despite decades of research. The measured properties of solar energetic particles (SEPs) have long been modeled in different particle-acceleration scenarios. The challenge has been to disentangle the effects of transport from those of acceleration. The Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) instrument enables unique observations of SEPs including the composition and angular distribution of the particles about the magnetic field, i.e., pitch angle distribution, over a broad energy range (>80 MeV)-bridging a critical gap between space-based and ground-based measurements. We present high-energy SEP data from PAMELA acquired during the 2012 May 17 SEP event. These data exhibit differential anisotropies and thus transport features over the instrument rigidity range. SEP protons exhibit two distinct pitch angle distributions: a low-energy population that extends to 90 degrees and a population that is beamed at high energies (>1 GeV), consistent with neutron monitor measurements. To explain a low-energy SEP population that exhibits significant scattering or redistribution accompanied by a high-energy population that reaches the Earth relatively unaffected by dispersive transport effects, we postulate that the scattering or redistribution takes place locally. We believe that these are the first comprehensive measurements of the effects of solar energetic particle transport in the Earth's magnetosheath.
|
|
24. |
- Adriani, O., et al.
(author)
-
Positrons and electrons in primary cosmic rays as measured in the PAMELA experiment
- 2009
-
In: Bulletin of the Russian Academy of Sciences: Physics. - 1062-8738. ; 73:5, s. 568-570
-
Journal article (peer-reviewed)abstract
- The PAMELA experiment is being carried out on board the Russian satellite Resurs DK1 placed in the near-earth near-polar orbit on June 15, 2006. The apparatus comprising a silicon-strip magnetic spectrometer and an electromagnetic calorimeter allows measurement of electron and positron fluxes in cosmic rays in a wide energy interval from ∼100 MeV to hundreds of GeV. The high-energy electron and positron separation technique is discussed and the data on positron-to-electron ratio in primary cosmic rays up to E ≃ 10 GeV from the 2006 - 2007 measurements are reported in this work.
|
|
25. |
- Adriani, O., et al.
(author)
-
Secondary electron and positron fluxes in the near-Earth space observed in the ARINA and PAMELA experiments
- 2009
-
In: Bulletin of the Russian Academy of Sciences: Physics. - 1062-8738. ; 73:3, s. 364-366
-
Journal article (peer-reviewed)abstract
- Secondary electron and positron fluxes in the energy range from 3 MeV to 7 GeV were measured with the ARINA and PAMELA spectrometers onboard the Resurs-DK satellite launched on June 15, 2006 into an elliptical orbit with an inclination of 70.4° and an altitude of 350-600 km. It is shown that positrons dominate over electrons by a factor of up to 4-5 in the geomagnetic equator region (L < 1.2 and B > 0.25).
|
|