28 GHz Gyrotron Heating Plans for LDX

The success of fully levitated LDX plasma operations is now motivating increasing the heating power to explore the full potential of high beta plasma stability in a dipole magnetic configuration. Plans are underway to install a Varian model VGA-8050M 28 GHz gyrotron that is capable of 200 kW in 100 ms pulses or 30 kW for up to 10 seconds. This will make possible the generation of plasma densities up to the 10$^{13}$ cm$^{-3}$ range which are presently not accessible with the current 2.45 to 10.5 GHz heating sources. It will also significantly increase maximum heating power above the present 15 kW to access higher beta plasmas. The 63.5 mm diameter TE$_{01}$ mode gyrotron output will be down tapered for transmission in 38.1 mm i.d. smooth walled copper straight waveguide and available corrugated 90\r{ } bends. Transmission losses are estimated to be less than 5{\%} over 40 m. A launch antenna in LDX will direct the beam to the 1~Tesla resonance region. A layout of the planned system will be presented.