Characteristics of ion Bernstein wave heating on the JIPP T-IIU tokamak

Abstract

Ion Bernstein Wave (IBW) heating has been examined on the JIPP T-IIU tokamak under two different conditions referred to as Mode-I and Mode-II. In the Mode-I regime, a wave is launched on an IBW branch between the third and fourth cyclotron harmonics of deuterium ions. In the Mode-II regime, a wave is launched on a branch between the second and third cyclotron harmonics. These two modes show quite different heating characteristics. The causes of this difference are analysed by using a simple model to determine the k, spectrum of the excited wave and by applying a ray tracing code. In connection with the Mode-I experiment as discussed in a previous report (1985), two important new experimental results are obtained. It is shown that an IBW heats the core of the plasma rather than causing plasma-edge interaction, as anticipated. It is also shown that the energy tail of the hydrogen ions is higher than that of the deuterium ions, which indicates that the responsible heating mechanisms are different.

Observation of parametric decay instability during ion Bernstein wave heating experiments on HT-7

“…IBW heating in tokamaks is based on the fact that the finite Larmor radius waves in the range of the ion cyclotron frequency excited from the low-field side of machine can penetrate into the hot plasma core without strong attenuation until the waves approach the harmonic cyclotron layers. Good ion heating resulting from IBW heating were observed on Alcator-C [1], PLT [2], PBX [3] and JIPP-II-U [4][5][6]. A simultaneous electron temperature and density rise with peaking of the profiles was observed in the high-frequency IBW experiment on FTU [7].…”

Laboratory simulations of suprauroral mechanisms leading to perpendicular ion heating and conic formation

“…As [Ogawa et al , 1987;Fukayarna et al 1976]. In addition to multiple harmonics, waves were produced at fractions of the input frequency (see Figure 11).…”

“…It is tempting to speculate that the same mechanism may be operative in the suprauroral region, particularly since the ratios of beam streaming energy to thermal energy are also similar for observed suprauroral beams and the present laboratory beams. [Ogawa et al , 1987;Fukayarna et al 1976]. In addition to multiple harmonics, waves were produced at fractions of the input frequency (see Figure 11).…”

Suppression of MHD instabilities by ion Bernstein wave (IBW) heating in the HT-7 tokamak

“…Both ion and electron heating via linear and nonlinear processes have been observed on quite a few devices ,e.g. on JIPP-II-U [2][3][4], PLT [5], PBX-M [6] and Alcator-C [7]. Nevertheless, noted also the MHD instabilities were suppressed during IBW heating experiment in PBX-M, and bootstrap current induced in mid minor radius region broadened the total current profile.…”