TITLE

Ion cyclotron range of frequency heating experiments on the large helical device and high energy ion behavior

AUTHOR(S)
Kumazawa, R.; Mutoh, T.; Seki, T.; Watari, T.; Saito, K.; Torii, Y.; Shimpo, F.; Nomura, G.; Yokota, M.; Kato, A.; Hartmann, D. A.; Zhao, Y.; Fukuyama, A.; Okada, H.; Ohkubo, K.; Sato, M.; Kubo, S.; Shimozuma, T.; Idei, H.; Yoshimura, Y.
PUB. DATE
May 2001
SOURCE
Physics of Plasmas;May2001, Vol. 8 Issue 5, p2139
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Ion cyclotron range of frequency (ICRF) heating experiments on the Large Helical Device (LHD) [O. Motojima et al. Fus. Eng. Des. 20, 3 (1993)] achieved significant advances during the third experimental campaign carried out in 1999. They showed significant results in two heating modes; these are modes of the ICH-sustained plasma with large plasma stored energy and the neutral beam injection (NBI) plasma under additional heating. A long-pulse operation of more than 1 minute was achieved ata level of 1 MW. The characteristics of the ICRF heated plasma are the same as those of the NBI heated plasma. The energy confinement time is longer than that of International Stellarator Scaling 95. Three keys to successful ICRF heating are as follows: (1) an increase in the magnetic field strength, (2) the employment of an inward shift of the magnetic axis, (3) the installation of actively cooled graphite plates along the divertor legs. Highly energetic protons accelerated by the ICRF electric field were experimentally observed in the energy range from 30 to 250 keV and the tail temperature depended on the energy balance between the wave heating and the electron drag. The transfer efficiency from the high energy ions to the bulk plasma was deduced from the increase in the energy confinement time due to the high energy ions in the lower density discharge, which agrees fairly well with the result obtained by the Monte Carlo simulation. The transfer efficiency is expected to be 95% at an electron density of more than n[sub e] = 5.0 × 10[sup 19] m[sup -3] even in the high power heating of 10 MW. The accumulation of impurities, e.g., FeXVI and OV was not observed in high rf power and long pulse operation. The well-defined divertor intrinsic to LHD is believed to be useful in reducing the impurity influx.
ACCESSION #
4716493

 

Related Articles

  • Stabilization of interchange modes in mirror plasmas by resonant coupling to ion-cyclotron sidebands. Stefan, V.; McBride, J. B. // Physics of Fluids (00319171);Nov85, Vol. 28 Issue 11, p3189 

    Based on a nonlinear, local mode–mode coupling relation, the resonant interaction of flute-interchange modes with radio frequency (rf ) wave fields in the ion-cyclotron range of frequencies (ICRF) is studied. It is shown that interchange modes can be stabilized because of resonant...

  • Trapped ion absorption of non-Maxwellian plasmas in ion cyclotron radio-frequency heating. Chen, Yan Ping; Tsai, Shih Tung // Physics of Fluids B: Plasma Physics;Aug93, Vol. 5 Issue 8, p2739 

    The nonlocal power absorption of trapped ions in ion cyclotron radio-frequency heating is calculated for several non-Maxwellian distribution functions by keeping the full particle orbit and wave coupling. For slowing down distribution the finite Larmor radius effect enhances the power absorption...

  • Control of plasma parameters in sheet-shaped electron cyclotron resonance heating plasma... Shibata, Kanetoshi; Yugami, Noboru; Nishida, Yasushi; Miyazaki, Tadaomi // Review of Scientific Instruments;Apr96, Vol. 67 Issue 4, p1502 

    Describes the production and parameter control techniques of sheet-shaped cyclotron resonance heating (ECRH) plasma. Supplementing radio frequency by the sheet-shaped electron cyclotron plasma; Application to the material processing in well defined manner.

  • Scrape-off layer profile modifications by convective cells. Myra, J.R.; D'lppolito, D.A. // Physics of Plasmas;Feb96, Vol. 3 Issue 2, p699 

    Studies the effect of convective cells (CC) on transport in the scrape-off layer in the regime where the density gradient scale length and the cell size are comparable. Importance of CCs in understanding density profile modifications induced by ion cyclotron range of frequencies antennas; Use...

  • Passive cyclotron current drive efficiency for relativistic toroidal plasmas. Kasilov, S.V.; Kernbichler, W. // Physics of Plasmas;Nov96, Vol. 3 Issue 11, p4115 

    Presents the results of analytical and numerical studies of the passive cyclotron current drive efficiency in mildly relativistic toroidal plasmas. Conditions under which the separation of the electron and photon balance equations occurs; Reduced variational principle for the current drive...

  • Fast wave current drive in the ion cyclotron frequency range from the single-particle point of view. Bilato, R.; Brambilla, M. // Physics of Plasmas;Jan2003, Vol. 10 Issue 1, p179 

    The quasilinear model is commonly used to determine the heating rate and the current drive efficiency of the fast wave in the ion cyclotron range of frequency. The validity of this model at these frequencies is a controversial issue [Bécoulet et al., Phys. Plasmas 1, 2908 (1994)]. Here this...

  • Inverse ion-cyclotron damping: Laboratory demonstration and space ramifications. Koepke, M. E.; Teodorescu, C.; Reynolds, E. W.; Chaston, C. C.; Carlson, C. W.; McFadden, J. P.; Ergun, R. E. // Physics of Plasmas;May2003, Vol. 10 Issue 5, p1605 

    The familiar and ubiquitous phenomenon of ion-cyclotron damping is shown to be invertible in a laboratory plasma resembling ionospheric plasma in terms of important dimensionless parameters. The ion-cyclotron waves that arise spontaneously appear at all harmonics of the ion-cyclotron frequency,...

  • Simulations and theories of relativistic ion cyclotron instabilities driven by MeV alpha particles in thermal deuterium plasmas. Chen, K. R. // Physics of Plasmas;May2003, Vol. 10 Issue 5, p1315 

    The harmonic relativistic ion cyclotron instabilities driven by MeV alpha particles in magnetized thermal deuterium plasmas are studied with a perturbation theory, a kinetic theory, and particle-in-cell simulations. Due to the mass deficit of alphas, the resonant harmonic cyclotron frequency of...

  • Measurements of the Microwave Power Absorbed by a Plasma during Second Harmonic ECR Heating in the L-2M Stellarator. Akulina, D. K.; Batanov, G. M.; Berezhetskiı, M. S.; Voronov, G. S.; Gladkov, G. A.; Grebenshchikov, S. E.; Donskaya, N. P.; Kolik, L. V.; Larionova, N. F.; Meshcheryakov, A. I.; Sarksyan, K. A.; Fedyanin, O. I.; Kharchev, N. K.; Khol’nov, Yu. V.; Shchepetov, S. V. // Plasma Physics Reports;Jan2002, Vol. 28 Issue 1, p7 

    Comparative measurements of the absorbed microwave power are performed using the diamagnetic diagnostics and a multichannel diagnostics receiving the second harmonic electron cyclotron emission from the plasma. The specific features of the experiments and the results obtained are discussed. ©...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics