Design and Commissioning of the ICRF Heating System on WHAM

The Wisconsin HTS Axisymmetric Mirror (WHAM) experiment is a record-setting magnetic mirror with 𝐵_max = 17 𝑇 and a variable mirror ratio of 15 − 50 under operation at the University of Wisconsin-Madison. This poster will review the Ion Cyclotron Range-of Frequencies (ICRF) heating system, which is intended to launch a fast magnetosonic wave between 3-26 MHz to accelerate the fast ion population at the second and third cyclotron harmonic resonance. Additional ICRF research goals include exploring the effect of pondermotive forces on MHD instabilities, the control of ion distribution functions in the presence of the loss cone and ICRF wall conditioning techniques.

We will report on the commissioning progress of the “Archimedes” 1 MW continuous-wave transmitter, which will offer a record-setting 25 kW/L RF power density. To deliver this heating power, the optimization and installation of the impedance matching network based on 4 tunable vacuum capacitors will be described alongside the engineering design of the m=0 ICRF antenna and a high power coaxial vacuum feedthrough upgrade. Finally, we will give an overview of the suite of RF diagnostics and their development progress, including 3 bi-directional couplers, Rogowski coils, voltage probes, movable emissive probes, 20 RF B-dot probes in an axial and azimuthal array, and infrared imaging.