High throughput plasma mass separation requires rotation control in a high density multispecies plasmas. A preliminary mass separation device based on a helicon plasma operating in gas mixtures and featuring concentric biasable ring electrodes is introduced. Plasma profile shows strong response to electrode biasing. In light of floating potential measurements, the density response is interpreted as the consequence of a reshaping of the radial electric field in the plasma. This field can be made confining or de-confining depending on the imposed potential at the electrodes, in a way which is consistent with single particle orbit radial stability. Concurrent spatially resolved spectroscopic measurements suggest ion separation, with heavy to light ion emission line ratio increasing with radius when a specific potential gradient is applied to the electrodes.

Abstract. We present experimental results on a tape-drive based plasma mirror which could be used for a compact coupling of a laser beam into a staged laser driven electron accelerator. This novel kind of plasma mirror is suitable for high repetition rates and for high number of laser shots.

We report on femtosecond TALIF measurements of neutral density in a mirror plasma device. We have measured H density down to 1011 cm-3, and the dynamics of the H neutrals in quasi-CW and pulsed plasma.

A collisional-radiative (CR) model that extracts the electron temperature, T e, of hydrogen plasmas from Balmer-line-ratio measurements is examined for the plasma electron density, n e, and T e ranges of 1010–1015 cm−3 and 5–500 eV, respectively. The CR code, developed and implemented in Python, has a forward component that computes the densities of excited states up to n = 15 as functions of T e, n e, and the molecular-to-atomic neutral ratio r(H2/H). The backward component provides n e and r(H2/H) as functions of the Balmer ratios to predict the T e. The model assumes Maxwellian electrons. The density profiles of the electrons and of the molecular and atomic hydrogen neutrals are shown to be of great importance, as is the accuracy of the line-ratio measurement method.