Design and Initial Measurements from a Prototype Helicon Plasma Device for Turbulence Studies

Helicon plasmas are widely used in electric propulsion, plasma processing, and RF current drive due to their high ionization efficiency and dense, stable operation. These plasmas are typically generated in linear devices by launching an azimuthally rotating m=+1 helicon wave via an RF antenna in an axial magnetic field. However, turbulence in helicon plasmas such as drift-wave, Kelvin-Helmholtz, and ion-acoustic modes can significantly affect wave absorption and axial plasma transport. Despite extensive use of helicon sources, the conditions under which different turbulence regimes arise and how they impact plasma performance remain poorly understood. We present the design of a prototype helicon device for systematically studying turbulence regimes using a mirror Langmuir probe array. We report early measurements of plasma density and electron temperature obtained using an RF compensated double Langmuir probe and outline the planned deployment of the MLP array for time- and space-resolved fluctuation diagnostics.