Measurement of 3D Wavenumber of High Frequency Emission in the Madison Symmetric Torus (MST) Tokamak Plasma

High-frequency magnetic fluctuations from 37 MHz to 5.5 GHz have been measured with an insertable magnetic probe in MST tokamak plasma. Fluctuations are measured in plasma edge, up to , and digitized at 12.5 GHz. The previous probe measured magnetic fluctuations and wave numbers only in the toroidal and poloidal direction. A new high frequency magnetic probe capable of measuring all three (toroidal, poloidal, and radial) components has been built to measures the 3D wave number spectrum. The radial profile of magnetic fluctuations’ power spectrum and the 3D wave number may answer the question of how localized are the Whistler waves. Magnetic fluctuation and radial x-ray intensity are bursty and correlated consistent with pitch-angle scattering of energetic electrons. High frequency magnetic fluctuations are present in plasma with density less than 0.03x10¹⁹ m³, toroidal magnetic about 0.14 T, and plasma current in the range of 50-60 kA.The emission frequencies scale with the magnitude of the toroidal field. Toroidal and poloidal fluctuations are polarized at the dominate frequency lines. Modes at frequency 37 MHz and 3.2 GHz are elliptically polarized.The high frequency branch is a backward propagating wave, consistent with anomalous Doppler.