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Title: PAMELA’S MEASUREMENTS OF MAGNETOSPHERIC EFFECTS ON HIGH-ENERGY SOLAR PARTICLES

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° 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 ormore » 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.« less

Authors:
;  [1];  [2];  [3]; ;  [4]; ; ;  [5];  [6];  [7];  [8];  [9];  [10];  [11]; ;  [12];  [13]; ;  [14] more »; « less
  1. Department of Physics and Astronomy, University of Florence, I-50019 Sesto Fiorentino, Florence (Italy)
  2. Department of Physics, University of Naples “Federico II,” I-80126 Naples (Italy)
  3. Lebedev Physical Institute, RU-119991 Moscow (Russian Federation)
  4. University of Bari, I-70126 Bari (Italy)
  5. INFN, Sezione di Trieste, I-34149 Trieste (Italy)
  6. Ioffe Physical Technical Institute, RU-194021 St. Petersburg (Russian Federation)
  7. INFN, Sezione di Florence, I-50019 Sesto Fiorentino, Florence (Italy)
  8. Space Science Center, University of New Hampshire, Durham, NH (United States)
  9. INFN, Sezione di Bari, I-70126 Bari (Italy)
  10. INFN, Sezione di Naples, I-80126 Naples (Italy)
  11. KTH, Department of Physics, and the Oskar Klein Centre for Cosmoparticle Physics, AlbaNova University Centre, SE-10691 Stockholm (Sweden)
  12. INFN, Sezione di Rome “Tor Vergata,” I-00133 Rome (Italy)
  13. IFAC, I-50019 Sesto Fiorentino, Florence (Italy)
  14. Heliophysics Division, NASA Goddard Space Flight Center, Greenbelt, MD (United States)
Publication Date:
OSTI Identifier:
22518809
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 801; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; ANGULAR DISTRIBUTION; ANISOTROPY; ANTIMATTER; ASTROPHYSICS; GEV RANGE; HELIOSPHERE; INCLINATION; LIGHT NUCLEI; MAGNETIC FIELDS; MAGNETOSHEATH; MASS; MEV RANGE; SCATTERING; SOLAR PARTICLES; SUN

Citation Formats

Adriani, O., Bongi, M., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bruno, A., Boezio, M., Bonvicini, V., Carbone, R., Bogomolov, E. A., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carlson, P., Casolino, M., De Donato, C., Castellini, G., Christian, E. R., Nolfo, G. A. de, E-mail: georgia.a.denolfo@nasa.gov, and and others. PAMELA’S MEASUREMENTS OF MAGNETOSPHERIC EFFECTS ON HIGH-ENERGY SOLAR PARTICLES. United States: N. p., 2015. Web. doi:10.1088/2041-8205/801/1/L3.
Adriani, O., Bongi, M., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bruno, A., Boezio, M., Bonvicini, V., Carbone, R., Bogomolov, E. A., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carlson, P., Casolino, M., De Donato, C., Castellini, G., Christian, E. R., Nolfo, G. A. de, E-mail: georgia.a.denolfo@nasa.gov, & and others. PAMELA’S MEASUREMENTS OF MAGNETOSPHERIC EFFECTS ON HIGH-ENERGY SOLAR PARTICLES. United States. doi:10.1088/2041-8205/801/1/L3.
Adriani, O., Bongi, M., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bruno, A., Boezio, M., Bonvicini, V., Carbone, R., Bogomolov, E. A., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carlson, P., Casolino, M., De Donato, C., Castellini, G., Christian, E. R., Nolfo, G. A. de, E-mail: georgia.a.denolfo@nasa.gov, and and others. Sun . "PAMELA’S MEASUREMENTS OF MAGNETOSPHERIC EFFECTS ON HIGH-ENERGY SOLAR PARTICLES". United States. doi:10.1088/2041-8205/801/1/L3.
@article{osti_22518809,
title = {PAMELA’S MEASUREMENTS OF MAGNETOSPHERIC EFFECTS ON HIGH-ENERGY SOLAR PARTICLES},
author = {Adriani, O. and Bongi, M. and Barbarino, G. C. and Bazilevskaya, G. A. and Bellotti, R. and Bruno, A. and Boezio, M. and Bonvicini, V. and Carbone, R. and Bogomolov, E. A. and Bottai, S. and Bravar, U. and Cafagna, F. and Campana, D. and Carlson, P. and Casolino, M. and De Donato, C. and Castellini, G. and Christian, E. R. and Nolfo, G. A. de, E-mail: georgia.a.denolfo@nasa.gov and and others},
abstractNote = {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° 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.},
doi = {10.1088/2041-8205/801/1/L3},
journal = {Astrophysical Journal Letters},
number = 1,
volume = 801,
place = {United States},
year = {Sun Mar 01 00:00:00 EST 2015},
month = {Sun Mar 01 00:00:00 EST 2015}
}
  • A review is presented of reported mammalian studies in this field and investigations with cyclotron- and synchrotron-produced particles ranging up to 3- Bev energy are presented. For physicians, an introductory section is included concerning the physical properties and dosimetric considerations of the particles in order to clarify the pertinent facts essential to an understanding of the nature of the transfer, release, and absorption of energy during the traversal of living mammalian tissues by charged particles. This leads to a theoretical consideration of the future possibilities of the negative pi meson ( pi /sup -/ meson) which will ultimately be studiedmore » in the manner in which protons, deuterons, and alpha particles are now being investigated. The pi /sup -/ meson, having a negative charge, will be attracted into the atomic nucleus, and, because of its very strong interaction with nuclear matter, disappears like the photon with creation of an electron pair. Thus the pi /sup -/ meson is transformed upon interaction with nuclear matter into kinetic energy among the various fragments of the disintegrated nucleus. It is suggested that the pi / sup -/ meson may become valuable in medical research, particularly in therapeutic situations requiring a favorable tumor-toentrance dose ratio. In the last centimeter of flight the pi /sup -/ meson should deliver about 100 Mev, yielding a tumorto-entrance ratio of about 30: 1. By comparison, protons of about 130 Mev give a tumor-to-entrance ratio of something like 10.1. The pi /sup -/ beams are produced by directing protons from large accelerators against metal (usually Cu) targets. It is predicted that improvements in accelerator technology and in magneto-optical focusing of proton beams will make pion beams applicable to biological problems within a few years. Proton and deuteron dosimetry are discussed, as a background to a survey of early medical studies with high-energy particles. The particles and energy ranges employed have been protons from 10 to 660 Mev, deuterons from 20 to 400 Mev, and alpha particles from 40 to 910 Mev. Many studies have been devoted to the histopathological effects of irradiation upon the normal brain, pituitary, spinal cord, and to a very limited extent upon the peripheral nerves, lens of eye, and labyrinth, usually with local, but in some instances with whole-body irradiations, These basic studies bear a pertinent relation to certain problems in space medicine. High-energy proton beams have been demonstrated to be useful, with considerable precision, as a neurosurgical tool to ablate selected regions within the brain. Studies on the treatment of animal and human neoplasms, using the advantages that panticle radiation (Bragg- peak effect) have as compared to electromagnetic radiation, are discussed. (BBB)« less
  • A review is presented on the effects of protons, deuterons, and particles in mammals with a theoreticai consideration of the negative pi meson. An introductory section is included concerning the physical properties and dosi- metric considerations of the particles in order to clarify the pertinent facts essential to an understanding of the nature of the transfer, release, and absorption of energy during the traversal of living mammalian tissues by charged particles. 54 references are included. (P.C.H.)
  • The Proton/Electron Telescope (PET) on SAMPEX is designed to provide measurements of energetic electrons and light nuclei from solar, galactic, and magnetospheric sources. PET is an all solid-state system that will measure the differential energy spectra of electrons from [approximately]1 to [approximately]30 MeV and H and He nuclei from [approximately]20 to [approximately]300 MeV/nuc, with isotope resolution of H and He extending from [approximately]20 to [approximately]80 MeV/nuc. As SAMPEX scans all local times and geomagnetic cutoffs over the course of its near-polar orbit, PET will characterize precipitating relativistic electron events during periods of declining solar activity, and it will examine whethermore » the production rate of odd nitrogen and hydrogen molecules in the middle atmosphere by precipitating electrons is sufficient to affect O[sub 3] depletion. In addition, PET will complement studies of the elemental and isotopic composition of energetic heavy (Z > 2) nuclei on SAMPEX by providing measurements of H, He, and electrons. Finally, PET has limited capability to identify energetic positrons from potential natural and man-made sources.« less