Suppression of electron temperature due to an axial magnetic field in multi shell multi species gas puff z-pinches*

We report results from collective optical Thomson scattering in multi shell and multi species gas puff z-pinch plasmas investigated on the 1-MA, 200 ns COBRA pulsed power generator at Cornell University. The gas puff configuration consists of concentric outer (Ne gas) and inner (Ne gas) annular gas puffs with an Ar center jet. An axial magnetic field of either 0.1 or 0.2 Tesla was applied. We used a combination of multiple shells and external magnetic field to suppress Magneto Rayleigh Taylor Instability (MRTI).  We used the ion acoustic wave (IAW) feature to obtain both the electron and ion temperature of the plasma. Our results indicate that the use of multiple shell gas puffs and an external magnetic field reduces the amplitude of instabilities. Optical Thomson scattering results show that the electron temperature (in the range 0.02-0.08 keV) is suppressed (in the range 0.01-0.04 keV) when an axial magnetic field is applied. We will discuss a more detailed analysis of electron and ion temperature measurements and underlying physics behind electron temperature suppression.