The Yohkoh context for high-energy particles in solar flares

The Sun accelerates ions up to tens of GeV and electrons up to 100s of MeV in solar flares and coronal mass ejections. The energy in the accelerated tens-of-keV electrons and possibly ~1 MeV ions constitutes a significant fraction of the total energy released in a flare, implying that the particle acceleration and flare energy release mechanisms are intimately related. The total rate of energy release in transients from flares down to microflares/nanoflares may be significant for heating the active solar corona.Shock waves driven by fast CMEs appear to accelerate the high-energy particles in large solar energetic particle events detected at 1 AU. Smaller SEP events are dominated by ~1 to tens-of-keV electrons, with low fluxes of up to a few MeV/nucleon ions, typically enriched in 3He. The acceleration in gamma-ray flares appears to resemble that in these small electron-3He SEP events.

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THE RELATIONSHIP BETWEEN EXTREME ULTRAVIOLET NON-THERMAL LINE BROADENING AND HIGH-ENERGY PARTICLES DURING SOLAR FLARES

The Astrophysical Journal ◽

10.1088/0004-637x/775/2/122 ◽

2013 ◽

Vol 775 (2) ◽

pp. 122 ◽

Cited By ~ 2

Author(s):

T. Kawate ◽

S. Imada

Keyword(s):

Solar Flares ◽

Extreme Ultraviolet ◽

High Energy ◽

Line Broadening ◽

The Relationship ◽

High Energy Particles ◽

Thermal Line

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Plasma Energetics in Solar Flares

Highlights of Astronomy ◽

10.1017/s1539299600004081 ◽

1980 ◽

Vol 5 ◽

pp. 343-350 ◽

Cited By ~ 1

Author(s):

Gerard Van Hoven

Keyword(s):

Gamma Rays ◽

Solar Flares ◽

High Energy ◽

Physical Mechanisms ◽

Very High Energy ◽

Physical Effects ◽

High Energy Particles ◽

The Magnetic Field ◽

Dissipation Processes ◽

Very High

I want to begin with the observation, which I will try to make clear in the following, that a solar flare comprises an incredibly complex set of phenomena. This is not only true with respect to what is seen and measured in spectacular examples, but also when one considers the constituent parts of simple, even idealized, cases. A series of different physical effects lead, as one illustration, to radiations from the flare-instability site and its surroundings which span the range from meter waves to gamma rays (Svestka 1976, Sturrock 1979).To fit within the context of this discussion, I will concentrate on the high-temperature and quasi-thermal aspects of a flare, and on the basic physical mechanisms connected with the primary energization and dissipation processes. Thus, I will treat the reconnection of the magnetic field, the bulk acceleration of particles, the thermalization and the ultimate radiation of the energy. I will not treat the optical manifestations or, at the other extreme, the acceleration of very high energy particles.

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Particles and Energy Transport in the Solar Atmosphere during Solar Flares

International Astronomical Union Colloquium ◽

10.1017/s0252921100154442 ◽

1989 ◽

Vol 104 (2) ◽

pp. 321-324

Author(s):

Heristchi D. ◽

Raadu M.A. ◽

Vial J.-C. ◽

Malherbe J.-M.

Keyword(s):

Solar Atmosphere ◽

Solar Flares ◽

Energy Transport ◽

Interplanetary Medium ◽

High Energy ◽

Low Density ◽

Proposed Model ◽

Buoyancy Forces ◽

High Energy Particles

AbstractThe proposed model of particles transport in the solar atmosphere during flares consists in a low density plasmoid originating deep in the atmosphere and rising under magnetic and buoyancy forces. Confined particles are selectively released during the ascent and their interaction with the solar atmosphere produces X and γ bremsstrahlung. The characteristics of high energy particles released in the interplanetary medium are found to agree with observations.

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