Mode conversion and heating in a UCLA-high schools collaborative experiment

A small plasma device is in operation for use by undergraduates and high school students at UCLA. Magnetic field up to 100 G, with density $10^{8}\le n_{e} \le 10^{11}cm^{-3}$ and temperature $T_{e} <3eV$are available in a 50 cm diameter plasma 2 meters long. The plasma is generated by an ICP source at one end operating at about 500 kHz. For this experiment, a small plate located near the edge of the plasma column is used as an electrostatic launcher. High frequency waves $\omega_{ce} <\omega <3\omega_{ce} $are launched radially from the plate in the low-density region, with electric field perpendicular to B and to the density gradient. A Langmuir probe located some distance away axially measures plasma heating along a field line that passes several cm in front of the launcher, localized in radius with $\delta r\approx 1cm$ Absorption and strong electron heating are observed at the plasma resonant layer. We explore the ``double resonance condition at which $\omega_{pe} =2\omega_{ce} $. Here strong interaction with electron Bernstein waves is expected. The Bernstein waves are also launched at low power and their dispersion relation verified.