The participation of nuclei in type-III-related electron streams

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 charactefistic 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^–1 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 > 1.7 MeV helium flux be recognized ar the Earth distance.     

Charakteristik der Winter von Oravský Podzámok

Studia Geophysica et Geodaetica - Приводится оценка зим в...     

Longitudinal distribution of X-bremsstrahlung on the solar disc

In this paper, the dependence of the intensity of solar bremsstrahlung in the spectral range from 1–60 keV on heliographic longitude is investigated. Considering a flare mechanism, which assumes that the electrons move in a preferred direction in the course of their acceleration (according to the model of Takakura and Kai (1966) the electrons move parallel to the solar surface), we come to the conclusion that the maximum of the bremsstrahlung intensity is shifted with increasing electron velocity towards the direction of motion of electron beams. In the case of the Takakura and Kai flare mechanism, the slow electrons ( ), i.e. with small energies of 1–10 keV, reach the maximum of the bremsstrahlung intensity round the CM; for higher velocities ( ), i.e. for higher energies of 10–60 keV, the direction of the maximum is shifted away from the CM towards the disc limb. These theoretical conclusions were proved by experimental research conducted by means of satellites.