T(e)/T(i) effects on JET energy confinement properties
Lately the question has been raised if a modification of the energy-confinement scaling law with respect to the electron to ion temperature ratio, T(e)/T(i), is required. Theoretically, like in e.g. the Weiland model, the confinement is thought to degrade with T(e)/T(i) and studies of the hot-ion (T(i)>T(e)) mode seems to corroborate this. In this paper, it is shown that due to a number of effects that cancel each other out, the energy confinement time remains constant for T(e)/T(i) >/~ 1. The numerical study relies on a series of JET shots specifically designed to reveal an effect of T(e)/T(i) in the hot-electron (T(e)>T(i)) mode. A distinct effort was made to keep all current scaling-law parameters constant, including the total heating power. The effects that provide the constant confinement times have therefore nothing to do with the global properties of the plasma, but are rather due to variations in the temperature gradients which affects the transport locally.
Bibliographic Reference: An oral paper given at: 12th International Congress on Plasma Physics Organised by:CEA Research Centres, France Held at: Acropolis conference center, Nice (FR)
Availability: Available from Association EURATOM-CEA, Departement de Recherches sur la Fusion Controlee, CEA Cadarache, F-13108 St Paul-Lez-Durance, France Tel: (+33) 4 42 25 70 01; Fax: (+33) 4 42 25 64 21 E-mail: email@example.com
Record Number: 200417815 / Last updated on: 2004-12-01
Original language: en
Available languages: en