Measurement of Magnetic Field Fluctuation in a Field-Reversed-Configuration Plasma

Confinement magnetic field of a field-reversed-configuration (FRC) plasma is reduced by a factor of about 10 and plasma density is decreased by a factor of about 100 without lowering the temperature seriously by translating a theta-pinch produced FRC plasma axially into a large bore metal vessel. Reduced magnetic field brings the lower-hybrid frequency into a range easily detected by magnetic probes. Search for wave activities in the FRC plasma for a wide frequency range disclosed magnetic field fluctuations in the lower-hybrid-drift frequency range for the first time in the FRC plasma. The identification of the mode is not done yet but the fluctuation level is close to the values predicted by theories on the LHD instability. This fluctuation level is not large enough to account for the transport rate of the particles from the FRC plasma.