Geodesic acoustic mode spectroscopy

S. I. Itoh, K. Itoh, M. Sasaki, A. Fujisawa, T. Ido, Y. Nagashima

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


A new kind of plasma diagnostics, geodesic acoustic mode (GAM) spectroscopy, is proposed. Radial eigenmodes of GAMs with discrete eigenfrequencies in toroidal plasmas are analysed. The eigenmode has a wavelength of the order of (ρi the ion gyroradius, LT the temperature gradient scale length) and has the highest peak near the radius where the eigenfrequency coincides with the local GAM frequency. Therefore, observing the radial position of the highest peak of the eigenmode provides a method to measure the local ion sound velocity. A novel method to measure the ion composition is given, combined with densities and temperatures.

Original languageEnglish
Article numberL01
Pages (from-to)L7-L10
JournalPlasma Physics and Controlled Fusion
Issue number8
Publication statusPublished - Aug 1 2007

All Science Journal Classification (ASJC) codes

  • Nuclear Energy and Engineering
  • Condensed Matter Physics


Dive into the research topics of 'Geodesic acoustic mode spectroscopy'. Together they form a unique fingerprint.

Cite this