PHAse Space MeAsurements (PHASMA) Experiment

A new experiment, called the PHAse Space MeAsurements (PHASMA), features laser induced fluorescence diagnostics for ion measurements, Thomson scattering diagnostics for electron velocity distribution function measurements, and a microwave scattering system for turbulence measurements. PHASMA is designed to enable the direct measure­ment of ion and elec­tron vdfs in space-relevant plasma phenomena including reconnection, shocks, and turbulence. To create the conditions necessary for different experimental regimes, PHASMA will em­ploy a 5 kW, steady-state heli­con source ca­pable of gen­er­ating variable-den­sity back­ground hy­dro­gen, he­lium, and ar­gon plas­mas with control­lable plasma pressure (relative to the magnetic pressure), collisionality, and azi­muthal flow shear. Reconnecting flux ropes will be created through the merging of discharges from two pulsed plasma guns. Measurement objectives include fully 3D ivdf measurements in a 3D volume with spatial resolution less than 0.2 cm (the expected electron skin depth in PHASMA) and similarly resolved evdf measurements, in all three laboratory coordinate axes. We will present design specifications and initial construction results of PHASMA.