Elliot, H., Energetic Particles as a Source of Flare Energy, 342, 12 (1973) (ADS)
(click on the image for a larger version)
A cartoon from an era in which people still searched for the sources
of flare energy.
Nowadays, of course, we are all quite sure that
current systems in the corona - stressed magnetic fields - store
the energy prior to the event.
Elliot's model, however, stored it
in high-energy particles trapped in
magnetic mirrors.
This is a difficult theory to refute observationally, since the particles -
if ions - would not have many clear radiation signatures.
Note that the purpose of the "trapping region" here is to store energy
prior to the flare, rather than SEPs after the flare.
One significant implication of this cartoon is the difference in
philiosophy between solar-flare scholars coming from cosmic-ray
physics and from astronomy.
The cosmic-ray crowd (Elliot in the forefront) looked to the
non-thermal particles seen as very significant
outside stellar atmospheres.
Does the energy density in Galactic
cosmic rays not rival that of the starlight or the microwave
background?
The astronomy crowd, on the other hand, would prefer
an essentially thermal explanation, seen in current practice as the
prevalent MHD theories of flare development - these are
fluid theories, with no particles at all.
Of course, most of the easily
detected radiative signatures of flares come from relaxed (thermalized)
plasmas.
At present it seems as though the jury is still out
concerning the basic question of when to make the break between kinetic
and fluid approaches.
A cartoon from an era in which people still searched for the sources of flare energy. Nowadays, of course, we are all quite sure that current systems in the corona - stressed magnetic fields - store the energy prior to the event. Elliot's model, however, stored it in high-energy particles trapped in magnetic mirrors. This is a difficult theory to refute observationally, since the particles - if ions - would not have many clear radiation signatures. Note that the purpose of the "trapping region" here is to store energy prior to the flare, rather than SEPs after the flare.
One significant implication of this cartoon is the difference in philiosophy between solar-flare scholars coming from cosmic-ray physics and from astronomy. The cosmic-ray crowd (Elliot in the forefront) looked to the non-thermal particles seen as very significant outside stellar atmospheres. Does the energy density in Galactic cosmic rays not rival that of the starlight or the microwave background? The astronomy crowd, on the other hand, would prefer an essentially thermal explanation, seen in current practice as the prevalent MHD theories of flare development - these are fluid theories, with no particles at all. Of course, most of the easily detected radiative signatures of flares come from relaxed (thermalized) plasmas. At present it seems as though the jury is still out concerning the basic question of when to make the break between kinetic and fluid approaches.