[en] The construction of a new double probe circuit using wide band optically isolated electronic elements is described. The circuit is adaptable to measuring plasma characteristics generted by pulsed discharges. The entire system is powered by a high performance dc/dc converter. The probe and ramp generator circuits are at floating potential and possess an over-all capacity relative to ground <50 pF. The bandwidth of the probe circuit is better than 250 kHz

No abstract available

[en] A novel type of ion source was designed and constructed for studies of chemical ionization processes, using low energy ions produced from inorganic gases in a high frequency flow discharge. Temperature and electron density profiles were measured in the downstream of the discharge region by cylindrical Langmuir- and orifice-probes. Typical plasma temperatures and densities are: Tsub(e)=2-3 eV; nsub(e)=(0.5-2.0)x10¹¹ cm^-3. (Auth.)

No abstract available

[en] Magnetoacoustic resonance in a partially helium plasma is investigated. The results are compared with a numerical calculation and it is found, that the inhomogeneity strongly influences the shape of the field distribution but the amplification is only slightly affected. (orig.)

No abstract available

[en] The electron temperature of two different magnetically stabilized rf-discharges (argon at 0.6 Torr) has been measured by means of optical spectroscopy. The results are compared with measurements using Langmuir probes. The electron temperature in a plasma generated by a 50 MHz rf-field reaches 2.5 eV while the microwave-discharge-plasma with a comparable power level has only an electron temperature of 0.5 eV. (Auth.)

[en] Anomalous attenuation of magnetosonic oscillations driven in an r.f.-plasma and its dependence on the observed low-frequency density fluctuations are investigated. The fluctuations are identified by digital spectral analysis technique as unstable collisional drift modes leading to drift wave turbulence. A dielectric tensor accounting for the anisotropic turbulence is given and the anomalous attenuation of the externally driven oscillations is explained by the drift wave turbulence. The experiments are performed in a linear device. Typical plasma parameters are: mean electron density n-barsub(e) = 1.5x10¹² cm^-3, electron temperature Tsub(e) = 2.5 eV, magnetic field B₀ = 2 kG, filling gas pressure p₀ = 3x10^-4 torr argon. (author)

[en] Magnetoacoustic oscillations are excited in an inhomogeneous magnetized plasma cylinder by amplitude modulation of a high frequency field (2.45 GHz, 3 kW PEP). The antenna is a long helical slow-wave structure. The axial field-oscillating with the modulation frequency (2/15 MHz) is monitored by means of electrostatically shielded magnetic probes. Resonance behaviour is observed around the eigenfrequency of the plasma cylinder. Power absorption is measured with diamagnetic loop technique. The plasma parameters are: mean electron density 3x10¹² cm^-3, electron temperature 3.5 eV, magnetic field 1.6 kG, filling gas 7x10^-4 Torr argon. (Auth.)

[en] Magnetoacoustic waves and resonance behavior, excited by an amplitude modulated rf field (ωsub(rf) >> ωsub(AM)) in a plasma cylinder, were observed. The modulated microwave power was coupled to the plasma by means of a simple slow-wave structure. (orig.)