Re-ionization of a partially ionized plasma by an Alfvén wave of moderate amplitude

1980 ◽  
Vol 24 (1) ◽  
pp. 65-74
Author(s):  
M. H. Brennan ◽  
M. L. Sawley
Keyword(s):  
Plasma Temperature ◽  
Torsional Wave ◽  
Alfven Wave ◽  
Helium Plasma ◽  
Acoustic Oscillations ◽  
Radial Density ◽  
Helium Ions ◽  
Wave Pulse ◽  
Partially Ionized ◽  
Doubly Charged

This paper reports on the use of forced magneto-acoustic oscillations to investigate the effect of a torsional hydromagnetic (Alfvén) wave pulse of moderate amplitude on the properties of a partially ionized afterglow helium plasma. Observations of the magnetic flux associated with the oscillations, measured at a number of frequencies, are used to determine radial density proffles and to provide estimates of plasma temperature. The torsional wave is shown to cause significant re-ionization of the plasma with no corresponding increase in the plasma temperature. The torsional wave is shown to cause significant re-ionization of the plasma with no corresponding increase in the plasma temperature. However, the presence of a number of energetic particles is evidenced by the production of a significant number of doubly charged helium ions.

Production of Doubly Charged Helium Ions

1954 ◽  
Vol 25 (11) ◽  
pp. 1058-1060 ◽  
Author(s):  
John W. Bittner
Keyword(s):  
Helium Ions ◽  
Doubly Charged

Alfvén wave propagation in a partially ionized plasma

2004 ◽  
Vol 11 (4) ◽  
pp. 1358-1365 ◽  
Author(s):  
Christopher Watts ◽  
Jeremy Hanna
Keyword(s):  
Wave Propagation ◽  
Alfven Wave ◽  
Partially Ionized

scholarly journals Effect of double layers on magnetosphere–ionosphere coupling

1987 ◽  
Vol 5 (2) ◽  
pp. 351-366 ◽  
Author(s):  
Robert L. Lysak ◽  
Mary K. Hudson
Keyword(s):  
Wave Propagation ◽  
Electric Field ◽  
Double Layer ◽  
Large Scale ◽  
Debye Length ◽  
Plasma Temperature ◽  
Auroral Zone ◽  
Alfven Wave ◽  
Scale Model ◽  
Double Layers

The earth's auroral zone contains dynamic processes occurring on scales from the length of an auroral zone field line (about 10RE) which characterizes Alfven wave propagation to the scale of microscopic processes which occur over a few Debye lengths (less than 1 km). These processes interact in a time-dependent fashion since the current carried by the Alfven waves can excite microscopic turbulence which can in turn provide dissipation of the Alfven wave energy. This review will first describe the dynamic aspects of auroral current structures with emphasis on consequences for models of microscopic turbulence. In the second part of the paper a number of models of microscopic turbulence will be introduced into a large scale model of Alfven wave propagation to determine the effect of various models on the overall structure of auroral currents. In particular, we will compare the effect of a double layer electric field which scales with the plasma temperature and Debye length with the effect of anomalous resistivity due to electrostatic ion cyclotron turbulence in which the electric field scales with the magnetic field strength. It is found that the double layer model is less diffusive than the resistive model leading to the possibility of narrow, intense current structures.

A new channel of the concentration decay of doubly charged helium ions in a plasma

2004 ◽  
Vol 97 (5) ◽  
pp. 673-676
Author(s):  
O. V. Zhigalov ◽  
Yu. A. Piotrovskii ◽  
Yu. A. Tolmachev
Keyword(s):  
Helium Ions ◽  
Doubly Charged

scholarly journals Measurement of stopping power of 240 MeV argon ions in partially ionized helium discharge plasma

2000 ◽  
Vol 18 (4) ◽  
pp. 647-653 ◽  
Author(s):  
M. OGAWA ◽  
U. NEUNER ◽  
H. KOBAYASHI ◽  
Y. NAKAJIMA ◽  
K. NISHIGORI ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Density ◽  
Target Thickness ◽  
Stopping Power ◽  
Helium Plasma ◽  
Discharge Ignition ◽  
The Mean ◽  
Argon Ions ◽  
Partially Ionized ◽  
Mean Charge

An energy loss of 240 MeV argon ions in a Z-pinch helium plasma has been for the first time observed throughout the entire pinching process. Standard Stark broadening analysis gives an electron density ranging from 4 to 6 × 1017 cm−3 during the pinch. To deduce stopping power from the energy loss, the target thickness of the helium plasma has been evaluated assuming the mean charge of helium based on thermal equilibrium. The observed electron density and the mean charge of helium give a target thickness of 30 ± 3 μg cm−2 from 1 μs to 1.8 μs after the discharge ignition. The measured stopping power exceeds a tabulated value for cold helium gas by a factor of 2 to 3 around the time of the first pinch. The experimental stopping power is compared with theoretical values calculated using an equation of stopping power for a partially ionized plasma.

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