Beam-induced pressure gradients in the early phase of proton-heated solar flares

Journal Article · Wed Oct 01 00:00:00 EDT 1986 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/164613· OSTI ID:6640543

Tamres, D H; Canfield, R C; Mcclymont, A N

The 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. 38 references.

• Research Organization: California Univ., San Diego
• OSTI ID: 6640543
• Journal Information: Astrophys. J.; (United States), Vol. 309
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
SOLAR FLARES
HEATING
PRESSURE GRADIENTS
ACCELERATION
CHROMOSPHERE
ENERGY SPECTRA
ENERGY TRANSFER
MOMENTUM TRANSFER
SOLAR PROMINENCES
SOLAR PROTONS
ATMOSPHERES
BARYONS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
NUCLEONS
PROTONS
RADIATIONS
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SOLAR PARTICLES
SOLAR RADIATION
SPECTRA
STELLAR RADIATION
640104* - Astrophysics & Cosmology- Solar Phenomena