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Beam-induced pressure gradients in the early phase of proton-heated solar flaresThe pressure gradient induced in a coronal loop by proton beam momentum deposition is calculated and compared with the thermal pressure gradient arising from nonuniform deposition of beam energy; it is assumed that the transfer of momentum and energy from beam to target occurs via the Coulomb interaciton. Results are presented for both a low mean energy and a high mean energy proton beam injected at the loop apex and characterized by a power-law energy spectrum. The present treatment takes account of the breakdown of the cold target approximation for the low-energy proton beam in the corona, where the thermal speed of target electrons exceeds the beam speed. It is found that proton beam momentum deposition plays a potentially significant role in flare dynamics only in the low mean energy case and only in the corona, where it may dominate the acceleration of target material for as long as several tens of seconds. This conclusion suggest that the presence of low-energy nonthermal protons may be inferred from velocity-sensitive coronal observations in the early impulsive phase.
Document ID
19870033194
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Tamres, David H.
(California Univ. San Diego, CA, United States)
Canfield, Richard C.
(California Univ. San Diego, CA, United States)
Mcclymont, A. N.
(California, University San Diego, United States)
Date Acquired
August 13, 2013
Publication Date
October 1, 1986
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 309
ISSN: 0004-637X
Subject Category
Solar Physics
Accession Number
87A20468
Funding Number(s)
CONTRACT_GRANT: NAGW-864
CONTRACT_GRANT: NSG-7406
CONTRACT_GRANT: NSF ATM-84-15793
Distribution Limits
Public
Copyright
Other

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