HELIUM ABUNDANCE AND DYNAMICS IN DIFFERENT TYPES OF SOLAR-WIND STREAMS - THE PROGNOZ-7 OBSERVATIONS

On the basis of the Prognoz 7 selective plasma measurements of alpha p articles and protons the correlations of helium parameters (relative a bundance n(alpha)/n(p), velocity difference Delta V = \V-alpha\ - \V-p \, and temperature ratio T-alpha/T-p) with bulk parameters in differen t types of solar wind streams are studied. Helium abundance increases with increasing wind velocity in quasi- stationary streams from 1.7 +/ - 2.6% in the heliospheric current sheet (HCS) up to 4.7 +/- 6.6% in t he coronal streamers (CS) and 6.6 +/- 8.0% in the coronal holes (CH). The maximum value of n(alpha)/n(p) of 10.5 +/- 10.1% is observed in co ronal mass ejections (CME) and an intermediate value between HCS and C S 3.4 +/- 4.2% in the shocked plasma. Helium abundance increases with increasing mass flux and density in streams from CHs and decreases in streams from CSs. Velocity difference Delta V increases with increasin g velocity in HCS and streams from CSs and CHs, but it is usually smal l or negative in CMEs and in shocked plasma. The temperature ratio T-a lpha/T-p increases with increasing velocity in the HCS and in streams from CSs, and it is approximately constant in streams from CHs, CMEs, and shocked plasma. No evidence has been obtained that the processes o f a particle acceleration differ from each other in streams from CSs a nd CHs, but they differ from the one in the HCS. In contrast to proces ses of acceleration, the processes of alpha particle heating in stream s from CHs and CSs are suggested to differ from each other, but they m ay be the same in streams from CSs and HCS. The value of alpha particl e and proton heating in streams from CHs increases with increasing abs olute value of velocity difference of alpha particles and protons.