[Kallenrode 1994 a]
The participation of nuclei in type-III-related electron streams
M. B. Kallenrode and Zdenek Svestka.
The participation of nuclei in type-III-related electron streams
Solar Physics, 155, 121-148.
1994
Contents
We study 27 increases of the flux of 300-800 keV electrons on board HELIOS A
or B, associated with intense type III radio bursts close to perihelion
passages of the two spacecraft, during the solar minimum.
Electrons can be detected inside cones with an angular width between 30°
and 60°.
Though only intense type III bursts are associated with recognizable
electron events in space, such an association does not exist for all of
them; this fact and great differences in fluxes of the individual events
indicate that, apart from the intensity, also some other characteristic of
the type III burst acceleration or propagation process determines the
resulting flux of electrons in space; the energy spectrum of the accelerated
electrons is one of the likely candidates.
A comparison of the electron flux in these events with the flux of
1.7-3.7 MeV/nucl helium reveals very large variations of the
helium/electron flux ratio, by a factor of at least 15 and
possibly much higher.
We demonstrate that these variations are not caused by propagation effects in
interplanetary space.
Therefore, they must be due either to propagation effects in the solar corona,
or more likely, to intrinsic variations in the relative production of
electrons and nuclei in the type III burst process.
An extrapolation of the observed fluxes to 1 AU shows that in only 7 of
the 27 electron events studied might a marginal greater than 1.7 MeV
helium flux be recognized at the Earth distance.
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