Investigations of Alfvén Modes at the Globus-M2 Tokamak Using a V-Band Multifrequency Doppler Reflectometer

We present new information on the development of Alfven modes on the Globus-M2 spherical tokamak. Data have been obtained using a V-band Doppler reflectometer with probing radiation frequencies from 50 to 75 GHz. Аs a multifrequency source of probing radiation, a microwave harmonic synthesizer has been used. As a result of using the new reflectometer, the toroidal Alfven mode localization in a magnetic field of 0.5 T has been obtained. The spectral components of the Alfven mode with Doppler frequency shifts caused by toroidal plasma rotation have been registered. In the central regions of the discharge, so-called “Alfven cascades” have been investigated.