The role of the density gradient on intermittent cross-field transport events in a simple magnetized toroidal plasma

Journal Article · Tue Apr 15 04:00:00 EDT 2008 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2901188· OSTI ID:21120235

Theiler, C; Diallo, A; Fasoli, A; Furno, I; Labit, B; Ricci, P ^[1]; Podesta, M ^[1]; Poli, F M ^[1]

---

1. Centre de Recherches en Physique des Plasmas-Ecole Polytechnique Federale de Lausanne, Association EURATOM-Confederation Suisse, CH-1015 Lausanne (Switzerland)

Intermittent cross-field particle transport events (ITEs) are studied in the basic toroidal device TORPEX [TORoidal Plasma EXperiment, A. Fasoli et al., Phys. Plasmas 13, 055902 (2006)], with focus on the role of the density gradient. ITEs are due to the intermittent radial elongation of an interchange mode. The elongating positive wave crests can break apart and form blobs. This is not necessary, however, for plasma particles to be convected a considerable distance across the magnetic field lines. Conditionally sampled data reveal two different scenarios leading to ITEs. In the first case, the interchange mode grows radially from a slab-like density profile and leads to the ITE. A novel analysis technique reveals a monotonic dependence between the vertically averaged inverse radial density scale length and the probability for a subsequent ITE. In the second case, the mode is already observed before the start of the ITE. It does not elongate radially in a first stage, but at a later time. It is shown that this elongation is preceded by a steepening of the density profile as well.

• OSTI ID: 21120235
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 4 Vol. 15; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DENSITY
EQUIPMENT
MAGNETIC FIELDS
PLASMA
PLASMA CONFINEMENT