QUASI-STATIONARY MAGNETIC-FIELDS IN HIGH-POWER MICROWAVE BEAM-GENERATED FLARE

A microwave flare produced by a beam of electromagnetic radiation (10( 4) W/cm(2) energy flux; 0.8 and 2.5 cm wavelengths) was studied. The a xial and radial (parallel to the microwave E field) components of the beam-generated quasi-stationary magnetic field were measured. This mag netic field was shown to arise in the microwave flare only after the a chievement of critical density n(e) = m omega(2)/4 pi e(2). The field is localized in the r, z less than or equal to lambda region, where th e plasma density is equal to or exceeds the critical density value; in the case of laser flare, the magnetic held is localized in the corona region filled with undercritical plasma. The magnetic field maximum v alue was 5.3 +/- 0.5 G, which corresponds to a 50 A current. The possi ble mechanisms of magnetic field generation in the microwave flare are discussed.