Fluctuation threshold and profile resilience in weakly ionized plasma in a curved, unsheared magnetic field
2004 (English)In: Physics of Plasmas, ISSN 1070-664X, Vol. 11, no 10, 4623-4633 p.Article in journal (Refereed) Published
A study of electrostatic fluctuations in a weakly ionized plasma confined by a purely toroidal magnetic field B is presented. At low B field the plasma is quiescent and transport is provided by stationary ExB flows along open equipotential surfaces. For B above a certain threshold, strong electrostatic fluctuations are excited, and the electron pressure profile on the low-field side is resilient with scale length much shorter than the threshold scale length for flute instability. At threshold the fluctuations exhibit the signatures of a monochromatic drift mode, and above threshold they are dominated by flute modes growing on the low-field side. Threshold behavior and profile resilience are explained as a two-stage process, where drift waves act as a seed for the unstable flute modes, and where a negative feedback mechanism involving anomalous transport regulates the electron pressure profile to maintain the imposed particle flux.
Place, publisher, year, edition, pages
2004. Vol. 11, no 10, 4623-4633 p.
toroidal plasma, coherent structures, drift waves, rotational transform, bispectral analysis, turbulence, transport, torus
IdentifiersURN: urn:nbn:se:kth:diva-23800DOI: 10.1063/1.1785155ISI: 000224456900016OAI: oai:DiVA.org:kth-23800DiVA: diva2:342499
QC 201005252010-08-102010-08-10Bibliographically approved