Status of the ECLAIR Magneto-inertial Fusion Experiment at Helicity Space

ECLAIR is an experiment to investigate the dynamics and scaling of 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 focus and undergo magnetic reconnection heating. A peristaltic magnetic nozzle then compresses, heats, and exhausts the preheated plasma.

We have launched plasma jets from all four guns at a common focus, where they merge into a single plasma which flows along the magnetic nozzle. We will present measurements of the density, temperature, velocity, and magnetic field structure of the plasma as the jets evolve through the four stages of formation, merging, compression, and exhaust.

The diagnostic suite includes time resolved, 129-chord ion doppler spectroscopy, 4-chord heterodyne interferometry,8 magnetic probe arrays with 16 clusters of 3D B-dot coils each, Rogowski coils, and a ballistic pendulum for thrust measurements. These diagnostics are placed along the ECLAIR geometry to measure plasma properties throughout the formation, merger, compression and exhaust sequence.

The first objective is to demonstrate that ECLAIR, 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). The second objective is to refine the requirements for a second-generation device (ECLAIR II) capable of heating and compressing a plectoneme to conditions that produce thermal neutrons.

[1] S. You, AIAA Propulsion & Energy, AIAA-2020-3835 (2020)