Simulation Studies of Fast Wave Launchers for Current Drive in TOKOMAK using COMSOL Multiphysics®
Helicon current drive is gaining the attention of plasma community to achieve off-axis study state plasma operation for longer duration for high electron density conditions. RF launchers are used to launch the helicon waves to the desired region of the current drive inside the plasma. A combline travelling wave antenna is one such type of a launcher which is used to launch helicon fast waves onto the plasma. It is a two port launcher such that power is fed into the input port and output port is connected to the dummy load. A fraction of power is radiated from first element of the combline antenna while the remaining power is coupled to the adjacent element. This process continues throughout the antenna. Subsequently, the remaining power is deposited in a dummy load.
This paper presents with simulation studies of combline antenna for steady state superconducting (SST-1) tokamak at Institute for Plasma Research (IPR) for operating frequency of 500 MHz in COMSOL Multiphysics®. For this antenna design, RF module is used. The design of an antenna can be optimized with the RF module by investigating various effect such as electromagnetic wave propagation inside the plasma, high power handling capacity.
