TITLE

Runaway-loss induced negative and positive loop voltage spikes in the Aditya Tokamak

AUTHOR(S)
Paradkar, Bhooshan; Ghosh, J.; Chattopadhyay, P. K.; Tanna, R. L.; Raju, D.; Bhatt, S. B.; Rao, C. V. S.; Joisa, Sankar; Banerjee, Santanu; Manchanda, R.; Gupta, C. N.; Saxena, Y. C.; Aditya Team
PUB. DATE
September 2010
SOURCE
Physics of Plasmas;Sep2010, Vol. 17 Issue 9, p092504
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Negative spikes followed by positive ones in the loop voltage signal during the discharge are observed in the Aditya Tokamak [S. B. Bhatt et al., Indian J. Pure Appl. Phys. 27, 710 (1989)]. These spikes are always accompanied by hard x-ray bursts caused by sudden loss of runaway electrons. The observed growth of m=3 mode seemed responsible for the losses of localized beams of runaway electrons (Eγ∼1-5 MeV) from the plasma region around q=3 magnetic surface. The movement of these runaway electrons during their extraction from inside the plasma induces both positive and negative electric fields at those locations. In this paper, a one-dimensional toroidal electric field diffusion model is used to estimate the induced electric field at the plasma boundary, which matches quite well with the observed spikes in loop voltage in both magnitude as well as its temporal evolution.
ACCESSION #
54050006

 

Related Articles

  • Understanding and predicting the dynamics of tokamak discharges during startup and rampdown. Jackson, G. L.; Politzer, P. A.; Humphreys, D. A.; Casper, T. A.; Hyatt, A. W.; Leuer, J. A.; Lohr, J.; Luce, T. C.; Van Zeeland, M. A.; Yu, J. H. // Physics of Plasmas;May2010, Vol. 17 Issue 5, p056116 

    Understanding the dynamics of plasma startup and termination is important for present tokamaks and for predictive modeling of future burning plasma devices such as ITER. We report on experiments in the DIII-D tokamak that explore the plasma startup and rampdown phases and on the benchmarking of...

  • Collisional diffusion in toroidal plasmas with elongation and triangularity. Martín, P.; Castro, E.; Haines, M. G. // Physics of Plasmas;May2007, Vol. 14 Issue 5, p052502 

    Collisional diffusion is analyzed for plasma tokamaks with different ellipticities and triangularities. Improved nonlinear equations for the families of magnetic surfaces are used here. Dimensionless average velocities are calculated as a function of the inductive electric field, elongation,...

  • Observation of an impurity hole in a plasma with an ion internal transport barrier in the Large Helical Device. Ida, K.; Yoshinuma, M.; Osakabe, M.; Nagaoka, K.; Yokoyama, M.; Funaba, H.; Suzuki, C.; Ido, T.; Shimizu, A.; Murakami, I.; Tamura, N.; Kasahara, H.; Takeiri, Y.; Ikeda, K.; Tsumori, K.; Kaneko, O.; Morita, S.; Goto, M.; Tanaka, K.; Narihara, K. // Physics of Plasmas;May2009, Vol. 16 Issue 5, p056111 

    Extremely hollow profiles of impurities (denoted as “impurity hole”) are observed in the plasma with a steep gradient of the ion temperature after the formation of an internal transport barrier (ITB) in the ion temperature transport in the Large Helical Device [A. Iiyoshi et al.,...

  • High-current electron beam in a hollow-cathode gas discharge at elevated pressures (∼100 Torr). Sorokin, A. R. // Technical Physics Letters;May2007, Vol. 33 Issue 5, p392 

    A discharge with plasma filling a flat-bottom cavity of depth δ in the cathode, partly closed by a dielectric plate with a hole (determining the aperture of the discharge between the cavity bottom and the anode), has been studied. In a discharge cell of type 1 with δ = 0.5 mm and a hole...

  • Estimation of the Longitudinal Electric Field Produced by a Relativistic Electron Beam in a Plasma. Vladyko, V. B. // Technical Physics;May2001, Vol. 46 Issue 5, p640 

    An axially symmetric model is used to analytically estimate the longitudinal electric field created in a plasma by an injected electron beam. The relationship can be used to estimate the electron beam energy loss in the range of parameters where theoretical studies rely only on numerical...

  • Power deposition and current drive by intense microwave beams in tokamaks. Kritz, Arnold H.; Smith, Gary R.; Nevins, William McCay; Cohen, R. H. // Physics of Fluids B: Plasma Physics;Jan89, Vol. 1 Issue 1, p142 

    Electron trapping by intense wave electric fields can alter the power deposition of electron-cyclotron waves in a tokamak when high-power sources are employed. The effect of wave trapping is examined in a ray-tracing study that utilizes plasma and wave parameters appropriate for the Microwave...

  • Neoclassical rotation of tokamak plasmas in the plateau regime. Novakovskii, S. V.; Galeev, A. A. // Physics of Plasmas;Oct95, Vol. 2 Issue 10, p3566 

    Studies the poloidal rotation of tokamak plasmas in the plateau regime. Determination of the relaxation rate; Time-dependent parallel viscosity; Plateau collisionality parameter; Derivation of an evolutionary equation for the radial electric field.

  • Acceleration of electrons in the vicinity of a lower hybrid waveguide array. Fuchs, V.; Goniche, M.; Demers, Y.; Jacquet, P.; Mailloux, J. // Physics of Plasmas;Nov96, Vol. 3 Issue 11, p4023 

    Studies the interaction of tokamak plasma edge electrons with the electric near field generated by a lower hybrid slow wave antenna. Tendency of the higher-order modes to overlap in the phase-space; Induction of the electron global stochasticity; Progress of electrons through accessible phase...

  • Effect of ExB flows on global linear ion temperature gradient modes. Maccio, M.; Vaclavik, J.; Villard, L. // Physics of Plasmas;Mar2001, Vol. 8 Issue 3, p895 

    Strong electric fields generate an ExB rotation of the equilibrium plasma. Experiments have shown that this effect could lower the anomalous transport in tokamaks. The study of the effect of these flows on the linear stability of ion temperature gradient (ITG) modes has therefore been...

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