Experimental and Numerical Analysis of the Impact of a Strong Permanent Magnet on Argon Plasma Flow

Abstract

The interaction between a probe body and argon plasma flow is investigated to examine to what extent the thermal loads on a vehicle during the re-entry into the Earth’s atmosphere can be reduced by applying a magnetic field. The experiments are performed using a strong permanent magnet installed inside a probe body of the so called European standard. An insert of high magnetic permeability was used to increase the magnetic field strength in front of the probe, which then was measured to be 0.12 T. Former investigations showed only weak influence on the bow shock geometry but definite impact on the temperature as well as on the boundary layer. In order to obtain a stronger interaction, several aspects of the setup have been revised. In contrast to earlier experiments, a spherical probe head is used in this investigation. Also, the plasma generator has been changed in order to achieve higher enthalpies und thus stronger magnetic interaction. The argon plasma condition had to be defined and first characterization measurements have been made. All experiments performed were steady state and the test duration was about 5 minutes. Pictures of the experiments were analyzed and showed a definite impact of the magnetic field on the bow shock geometry. Due to the magnet, the bow shock distance increased by roughly 13% whereas the recorded light intensity of the bow shock region increased by a factor of 2.7. The analysis of the center line intensity of each test case indicates that the magnetic field is affecting the argon plasma flow upstream, beyond the bow shock.