Location of Repository

Spectra of magnetic perturbations triggered by pellets in JET plasmas

By F. M. (Francesca) Poli, P. T. Lang, S. E. (Sergei E.) Sharapov, H. R. Koslowski, HASH(0x565525e6a320) and HASH(0x565525fe5bd8)

Abstract

Aiming at investigating edge localised mode (ELM) pacing for future application on ITER, experiments have been conducted on JET injecting pellets in different plasma configurations, including high confinement regimes with type-I and type-III ELMs, low confinement regimes and Ohmically heated plasmas. The magnetic perturbations spectra and the toroidal mode number, n, of triggered events are compared with those of spontaneous ELMs using a wavelet analysis to provide good time resolution of short-lived coherent modes. It is found that—in all these configurations—triggered events have a coherent mode structure, indicating that pellets can trigger an MHD event basically in every background plasma. Two components have been found in the magnetic perturbations induced by pellets, with distinct frequencies and toroidal mode numbers. In high confinement regimes triggered events have similarities with spontaneous ELMs: both are seen to start from low toroidal mode numbers, then the maximum measured n increases up to about 10 within 0.3 ms before the ELM burst

Topics: QC
Publisher: Institute of Physics Publishing Ltd.
Year: 2010
OAI identifier: oai:wrap.warwick.ac.uk:2673

Suggested articles

Preview

Citations

  1. (2001). A wavelet tour of signal processing, chapter 4. doi
  2. A wavelet-based method to measure the toroidal mode number of ELMs, proceeding of the ICPP, Fukuoka, accepted for publication in
  3. (1998). Analysis methods for multi-spacecraft data, chapter 1.
  4. (2009). P'or and ASDEX Upgrade Team, Investigation of pellet-driven magnetic perturbations in dierent tokamak scenarios, submitted to Plasma Phys. Control. Fusion doi
  5. (2008). Vinyar I et al The JET high frequency pellet injector, EFDA-JET-CP(08)04/08,

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.