Temperature and Lifetime Measurements in the SSX Wind Tunnel

Plasma

Gelber, Kaitlin D¹  Kaur, Manjit² 

[1]Author to whom correspondence should be addressed

[2]Department of Physics and Astronomy, Swarthmore College, Swarthmore, PA 19081, USA

关键词: taylor states;    magnetized plasma;    spectroscopy;    plasma lifetime;    equilibration rate;    e-folding time;   

DOI  :  10.3390/plasma1020020

学科分类：原子、分子光学和等离子物理

来源: mdpi

【 摘 要 】

We describe ion and electron temperature measurements in the Swarthmore Spheromak Experiment (SSX) MHD wind tunnel with the goal of understanding limitations on the lifetime of our Taylor-state plasma. A simple model based on the equilibrium eigenvalue and Spitzer resistivity predicted the lifetime satisfactorily during the first phase of the plasma evolution. We measured an average T e along a chord by taking the ratio of theCI I I97.7 nm toCI V155 nm line intensities using a vacuum ultraviolet (VUV) monochromator. We also recorded local measurements of T e and n e using a double Langmuir probe in order to inform our interpretation of the VUV data. Our results indicated that the plasma decayed inductively during a large part of the evolution. Ion Doppler spectroscopy measurements suggested that ions cooled more slowly than would be expected from thermal equilibration with the electrons, which maintained a constant temperature throughout the lifetime of the plasma.

【 授权许可】

CC BY