Development of fast ionization gauge for studying neutral flow dynamics in the BRB.*

Most of plasma sources on the BRB at the Wisconsin Plasma Physics Laboratory (WiPPL) require various types of gas injection mechanisms. The breakdown of the gas, and therefore the efficacy and reliability of the plasma source itself, is heavily dependent on the neutral gas density and flow characteristics; therefore, it is critical to understand the density profiles on the time timescales of the gas dynamics (1-10 kHz). We have planned to implement a fast ionization gauge similar to that used for other experiments ^[1,2] to get local density measurements on the timescales required. The fast ionization gauge is based on a modified Bayard-Alpert gauge ^[2] designed to be compact and mobile to allow measurement over a wide range of positions to acquire a more complete and accurate density profile of the neutral gas and have a better understanding of the plasma dynamics being studied.  

[1] You, Setthivoine, et al. "The Mochi LabJet experiment for measurements of canonical helicity injection in a laboratory astrophysical jet." The Astrophysical Journal Supplement Series 236.2 (2018): 29.

[3] Yun, Gunsu S., and Paul M. Bellan. "Plasma tubes becoming collimated as a result of magnetohydrodynamic pumping." Physics of Plasmas 17.6 (2010).

[2] T. E. Weber, T. P. Intrator; A compact fast ionization gauge for in situ measurement of high-density neutral flow dynamics. Rev Sci Instrum 1 April 2014; 85 (4): 043501