Properties of Turbulence and Stationary Zonal Flow on Transport Barrier in CHS

Spectral changes in electric field fluctuation are measured using twin heavy ion beam probes in CHS before and after an internal transport barrier is broken down. A wavelet analysis reveals intermittent behaviors of the fluctuations, and a significant correlation between fluctuation powers of the low (2.5 < f < 10 kHz) and high (30 < f < 250 kHz) ranges. The high frequency (turbulence) fluctuation increases with a decrease in the low frequency fluctuation after the back-transition. The change in the power distribution between these two frequency ranges may contribute to the improved transport on the barrier

Spectrograph of Electric Field Fluctuation in Toroidal Helical Plasma

This is a report on fluctuation measurements using twin heavy ion beam probes in CHS. The observation shows that a dozen of coherent modes with intermittent nature coexist in an electron cyclotron heated plasma. The modes are found to have long-distance correlation in toroidal direction. The radial structure of the modes are evaluated in potential fluctuation. The characteristics are not in contradictory with geodesic acoustic modes

The nature of premaximum halts of classical nova outbursts: V723 Cassiopeiae and V463 Scuti

We present a new interpretation of long premaximum halts of nova outbursts. For V723 Cas (Nova Cas 1995) and V463 Sct (Nova Sct 2000), we have reproduced light curves, excluding the brightness maxima, starting from the long premaximum halt through the late decay phase of the outbursts using a steady-state optically thick wind model. When the hydrogen-rich envelope of the white dwarf (WD) is massive enough, the star expands to \sim 100 R_\sun or over and its surface temperature decreases to below 7000 K. At this supergiant mimicry stage, the changes in both the photospheric radius and the temperature are small against the large increase in the envelope mass. These changes cause a saturation in visual magnitude that lasts a long time before it begins to decline. This saturation is known as the premaximum halt of a classical nova outburst. The visual magnitude during the saturation is close to the bolometric magnitude, which is an upper limit for a given WD mass. Since the WD masses are estimated to be 0.59 M_\sun for V723 Cas and 1.1 M_\sun for V463 Sct by fitting the decline rate of nova light curves, we can determine the absolute magnitude of premaximum halts. It is a refined Eddington luminosity. Thus, the premaximum halt of a nova works as a standard candle.Comment: corrections for distance estimate of V463 Sct and several typos, 8 pages including 5 figures, to appear in ApJL, 2004 September

Turbulence and Transport Characteristics of a Barrier in a Toroidal Plasma

Turbulence and zonal flow at a transport barrier are studied with twin heavy ion beam probes in a toroidal helical plasma. A wavelet analysis is used to extract turbulence properties, e. g., spectra of both density and potential fluctuations, coherence and phase between them, and the dispersion relation. Particle transport estimated from the fundamental characteristics is found to clearly rise with their intermittent activities after the barrier is broken down. The time-dependent analysis reveals that intermittency of turbulence is correlated with evolution of stationary zonal flow

Identification of Zonal Flows in a Toroidal Plasma

This Letter presents experimental confirmation of the presence of zonal flows in magnetically confined toroidal plasma using an advanced diagnostic system?dual heavy ion beam probes. The simultaneous observation of an electric field at two distant toroidal locations ( ~1.5 m apart) in the high temperature (~ 1 keV) plasma provides a fluctuation spectrum of electric field (or flow), a spatiotemporal structure of the zonal flows (characteristic radial length of ~ 1.5 cm and lifetime of ~1.5 ms), their long-range correlation with toroidal symmetry n = 0 , and the difference in the zonal flow amplitude with and without a transport barrier. These constitute essential elements of turbulence-zonal flow systems, and illustrate one of the fundamental processes of structure formation in nature

Properties of Antarctic Bottom Water observed by mooring system off Vincennes Bay

第3回極域科学シンポジウム/第35回極域気水圏シンポジウム 11月29日（木） 国立国語研究所 ２階多目的

Theory of Colloid and Interfacial Electric Phenomena

xvi;ill.;473hal.;26c