Status of Diagnostic Campaign for the ECLAIR Magneto-inertial Fusion Experiment at Helicity Space*

ECLAIR is an experiment designed to investigate the Helicity Drive magneto-inertial fusion concept [1]. ECLAIR models the Helicity Drive by producing four magnetized plectonemic Taylor states embedded in stable helical shear flow jets. These four jets merge at a common vertex and undergo magnetic reconnection heating. The peristaltic magnetic nozzle then compresses and heats the preheated plasma.

                In collaboration with groups at Caltech, UMBC, and Swarthmore, we are developing and installing a series of plasma diagnostics on ECLAIR to measure plasma temperature, density, velocity, and evolving magnetic fields. The initial diagnostic suite includes time resolved, multichord spectroscopy, 4-chord heterodyne interferometry, B-dot arrays, and Rogowski coils. These diagnostics are placed at key locations along ECLAIR to measure the plasma properties throughout the formation, merger, compression and exhaust sequence [2,3].

The objective is to quantitatively verify that our Helicity Drive concept, for the first time in a single integrated machine, 1) forms magnetized plectonemic jets as in past experiments (SSX, MOCHI), 2) undergoes magnetic reconnection-heating upon jet merging as in past experiments (SSX, UT, MAST), and 3) compresses with the peristaltic magnetic nozzle scheme shown previously at tabletop scale (Caltech).

We present the design and status of each diagnostic along with preliminary data. The goal is to strengthen the physics basis for extrapolating to higher temperature regimes.