Minimum Mach number for impulsive proton acceleration by parallel collisionless shock waves in solar flares

1989 ◽  
Vol 337 ◽  
pp. 954 ◽  
Author(s):  
Dean F. Smith ◽  
Stephen H. Brecht
Keyword(s):  
Mach Number ◽  
Shock Waves ◽  
Solar Flares ◽  
Collisionless Shock ◽  
Proton Acceleration

On Proton and Electron Acceleration by Shock Waves during Large Solar Flares

1978 ◽  
Vol 3 (3) ◽  
pp. 236-238
Author(s):  
V. M. Gubchenko ◽  
V. V. Zaitsev
Keyword(s):  
Shock Waves ◽  
Total Energy ◽  
Satisfactory Agreement ◽  
Solar Flares ◽  
Interplanetary Medium ◽  
Thermal Processes ◽  
Proton Acceleration ◽  
X Ray ◽  
Target Model ◽  
Γ Ray

Lin and Hudson (1976) have recently analysed non-thermal processes in proton flares, using observations of a series of major events in August 1972. They concluded that the 10–100 keV electrons accelerated during the flash phase account for the bulk of the total energy of a large proton flare (about 1032 – 1033 ergs); that most protons are accelerated later than the 10 — 100 keV electrons; and that most energetic protons escape to the interplanetary medium. Their conclusions with regard to proton acceleration are supported firstly by the delay of the maximum of γ-ray emission by 3-5 minutes after the maximum of X-ray emission, and secondly by the satisfactory agreement between the 7-ray spectrum and the thin-target model of emission. The energetic protons contain a very small fraction of the total flare energy (of the order of 10-5).

Experimental Study of High Mach Number Collisionless Shock Waves

Shock Tubes ◽  
1970 ◽  
pp. 463-474
Author(s):  
L. S. Levine ◽  
I. M. Vitkovitsky ◽  
A. C. Kolb
Keyword(s):  
Experimental Study ◽  
Mach Number ◽  
Shock Waves ◽  
Collisionless Shock ◽  
High Mach Number ◽  
High Mach

The form and energy of the shock waves from the solar flares of August 2, 4, and 7, 1972

1978 ◽  
Vol 83 (A3) ◽  
pp. 1035 ◽  
Author(s):  
G. N. Zastenker ◽  
V. V. Temny ◽  
C. D'Uston ◽  
J. M. Bosqued
Keyword(s):  
Shock Waves ◽  
Solar Flares

Shock Wave - Film Cooling Interactions in Transonic Flows

2001 ◽  
Author(s):  
P. M. Ligrani ◽  
C. Saumweber ◽  
A. Schulz ◽  
S. Wittig
Keyword(s):  
Shock Wave ◽  
Mach Number ◽  
Shock Waves ◽  
Film Cooling ◽  
Cross Flow ◽  
Injection Velocity ◽  
Film Cooling Effectiveness ◽  
Mach Numbers ◽  
Density Ratios ◽  
Film Cooling Holes

Interactions between shock waves and film cooling are described as they affect magnitudes of local and spanwise-averaged adiabatic film cooling effectiveness distributions. A row of three cylindrical holes is employed. Spanwise spacing of holes is 4 diameters, and inclination angle is 30 degrees. Freestream Mach numbers of 0.8 and 1.10–1.12 are used, with coolant to freestream density ratios of 1.5–1.6. Shadowgraph images show different shock structures as the blowing ratio is changed, and as the condition employed for injection of film into the cooling holes is altered. Investigated are film plenum conditions, as well as perpendicular film injection cross-flow Mach numbers of 0.15, 0.3, and 0.6. Dramatic changes to local and spanwise-averaged adiabatic film effectiveness distributions are then observed as different shock wave structures develop in the immediate vicinity of the film-cooling holes. Variations are especially evident as the data obtained with a supersonic Mach number are compared to the data obtained with a freestream Mach number of 0.8. Local and spanwise-averaged effectiveness magnitudes are generally higher when shock waves are present when a film plenum condition (with zero cross-flow Mach number) is utilized. Effectiveness values measured with a supersonic approaching freestream and shock waves then decrease as the injection cross-flow Mach number increases. Such changes are due to altered flow separation regions in film holes, different injection velocity distributions at hole exits, and alterations of static pressures at film hole exits produced by different types of shock wave events.

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