[en] Mean ionic charge of iron in He-3-rich solar flares and the average mean charge of silicon for 23 He-3-rich periods during the time interval from September 1978 to October 1979 were determined. It is indicated that the value of the mean charge state of silicon is higher than the normal flare average by approximately 3 units, and in perticular it is higher then the value predicted by resonant heating models for He-3-rich solar flares

[en] The ionic mass and charge composition of the suprathermal (10-230 keV/e) population of the plasma sheet has been measured using the Suprathermal Energy Ionic Charge Analyzer (SULEICA) on AMPTE/IRM before and after a substorm onset on April 8, 1985. Simultaneously with the substorm onset and strong earthward plasma flows, a flux increase of the suprathermal ions and a significant hardening of the spectra are observed that are most pronounced for O(+). The enhancement ratios can be best organized in terms of energy per charge. The observations are interpreted as an indication of particle acceleration by electric fields and additional injection of ionospheric plasma into the plasma sheet after substorm onset. 12 references

[en] The energy spectra and anisotropies of protons and alpha particles are investigated at the plasmasheet boundary during the recovery phase of geomagnetic substorms using the Max Planck Institut/University of Maryland sensor system on the ISEE-1 satellite. The observations are found to reveal the presence of a thin nonthermal layer of approximately 60 keV/charge protons and alpha particles at the plasmasheet boundary, the particles streaming highly collimated in earthward direction. It is pointed out that the alpha particle layer is confined within the proton layer. It is thought that the principal features of the layers can be explained in terms of an acceleration model proposed by Speiser (1965) for the environment of a magnetic neutral line

No abstract available

[en] A simple model for the particle balance in a reflex discharge with a superimposed axial magnetic field is presented based upon the results found for the negative glow of an anomalous glow discharge. The electron density and temperature of hydrogen and helium discharges are determined as functions of the discharge current, pressure and magnetic field; the ion current of a cylindrical Langmuir probe is evaluated according to the theory of Laframboise. Additional information on the ion composition of the plasma is obtained by comparison of the probe measurement with interferometric microwave measurements. The reflex discharge produces a negative glow plasma with Tsub(e) = 2000-3000⁰K and densities up to nsub(e) = 10¹³ cm^-3. For pressures below 0.01 Torr and strong magnetic fields the negative glow is transformed into a Penning discharge. (author)

No abstract available

[en] The structure and plasma parameters of a rotating plasma showing Alfven's critical velocity were investigated for the first time by means of Langmuir probes. It was demonstrated that the occurrence of the critical velocity is causally connected with the formation of a spoke structure. The electron temperature and the plasma density were determined with local resolution by which a detailed balance concerning the plasma density and the current transport became possible. The importance of turbulent electron heating for rapid ionization at the critical velocity is emphasized. In this process the modified two-stream-instability obviously plays an outstanding role. (orig.)

[en] Singly ionized energetic helium has been observed in the solar wind by using the time of flight spectrometer SULEICA on the AMPTE/IRM satellite between September and December, 1984. The energy density spectrum shows a sharp cut off which is strongly correlated with the four fold solar wind bulk energy. The absolute flux of the He(+)ions of about 10000 ion/sq cm.s is present independent of the IPL magnetic field orientation. The most likely source is the neutral helium of the interstellar wind which is ionized by solar UV radiation. It is suggested that these particles represent the source of the anomalous cosmic ray component

No abstract available

[en] The velocities of helium ions and neutrals are derived from Doppler shifted spectral lines He II 4686 A and He I 5876 A respectively. The ion velocity proves to be in accordance with the speed of rotating spokes which are usually observed in the build-up phase of rotating plasmas. It is demonstrated that the spoke velocity represents the plasma mass motion. Braking of plasma motion and acceleration of the neutrals to a value near Alven's critical velocity occurs within 10 μs. (orig.)