Current Sheet Tilt in a Radial Magnetic Shock Tube

Abstract

An experiment is carried out in a radial (inverse pinch) shock tube with argon of 50–400μ pressure and hydrogen of 100μ pressure. The current sheet was found to be tilted so that the cathode side lagged the anode side. At the anode the shock has a tilt in the same direction as the current sheet. At the cathode the shock is normal. These phenomena can be correlated by physical models which assume that the current is predominantly carried by the ions.

Gas-Fed Pulsed Plasma Thrusters: Fundamentals, Characteristics and Scaling Laws

“…This rule of thumb applies well to almost any geometry as demonstrated in other experiments as well, frequently without the authors realizing that they did meet the criteria [19,35,63]. It is also interesting to note that in many experiments where the sheet was classified not to be an effective sweeper [7,28,39], the sheet velocity scaled as the square-root of the energy to mass ratio as apposed to an expected linear scaling as predicted for effectively sweeping sheets [14,31,40,63]. In Ref.…”

“…Using an inverse z-pinch device, Johansson found that the tilting of the current sheet (which causes profile losses) increased for higher mass bit values [63]. Although the profile efficiency should effect both the thruster efficiency and the impulse-to-energy ratio, the existing models appear to predict the opposite trend.…”

“…In Ref. [63] Johansson, yet again at Avco-Everett, examined the current sheet tilt in an inverse z-pinch with hydrogen and argon at similar pressures. In this experiment, UV photo-detectors and magnetic field coils were used to measure the progression of the sheet.…”

A characteristic velocity for gas-fed PPT performance scaling

“…Using an inverse z-pinch device, Johansson found that the tilting of the current sheet (which causes profile losses) increased for higher mass bit values [18]. Although the profile efficiency should effect both the thruster efficiency and the impulse-to-energy ratio, the existing models appear to predict the opposite trend.…”

Physics and Dynamics of Current Sheets in Pulsed Plasma Thrusters

“…Since Johansson [37] was the only prior researcher to publish a theory for current sheet canting (which we termed the ion conduction current canting model), it is fitting that we should return to consider his conclusions, and compare them with the fast field penetration canting model put forth in the present study. Johansson proposed that a portion of the current sheet (of height h • ) will cant in order to direct ions toward the cathode.…”