Spatiotemporal Structure Of H Alpha Emission From The Detached Plasma In Gamma 10/Pdx

High-speed camera measurement was performed for analyses of detached plasma fluctuation in the GAMMA 10/PDX tandem mirror device. Significant spectral peaks at frequencies of 1.5 and 3 kHz were observed to have several local maxima along the vertical, near the entrance of the V-shaped target. Wavelet analysis indicated that 1.5- and 3-kHz fluctuations became non-simultaneously strong. Their phase relationships demonstrated inversion-symmetric and symmetric features with respect to the midplane. Such spectral patterns were interpreted as the line-integral of odd- and even-mode structures. It is suspected that the vertical edge part was due to radially elongated structures with an azimuthal phase shift. (C) 2019 The Japan Society of Plasma Science and Nuclear Fusion Research