000120103 001__ 120103
000120103 005__ 20180128005552.0
000120103 0247_ $$2doi$$a10.1088/0741-3335/46/5A/008
000120103 022__ $$a0741-3335
000120103 037__ $$aARTICLE
000120103 245__ $$aSynchronization of L-mode to H-mode transitions on the sawtooth cycle in Ohmic TCV plasmas
000120103 260__ $$c2004
000120103 269__ $$a2004
000120103 336__ $$aJournal Articles
000120103 500__ $$aSuppl. 5A
000120103 520__ $$aL-mode to H-mode transitions (LH transitions) are obtained in a wide range of plasma parameters in TCV Ohmic discharges. LH transitions either occur directly, indicated by a single abrupt drop in D-alpha emission, or present an intermediate 'dithering' phase before the H-mode state is attained, in which D-alpha emission shows rapid excursions between L-mode and H-mode levels. The type of transition, with or without a dithering phase, depends on the plasma current and plasma triangularity. It is less sensitive to plasma density and divertor geometry. The relative direction of the ion delB drift also plays a role in the characteristics of the LH transition. The time delay between an LH transition and the preceding sawtooth crash has been measured in every TCV H-mode discharge. Most LH transitions are found to occur in the first 30% of the sawtooth cycle, i.e. in the first 2 ms after a sawtooth crash. Moreover, LH transitions often occur soon after a large crash of a 'double sawtooth'. The distribution function of these time delays clearly indicates a synchronization of these two processes. However, the heat pulse released during a sawtooth crash has a transit time from the q = 1 surface to the plasma edge, which is much shorter than the time delay between the sawtooth crash and the LH transition.
000120103 700__ $$0240131$$aMartin, Y. R.$$g105777
000120103 773__ $$j46$$qA77-A85$$tPlasma Physics and Controlled Fusion
000120103 909C0 $$pCRPP
000120103 909C0 $$0252028$$pSPC
000120103 909CO $$ooai:infoscience.tind.io:120103$$particle$$pSB
000120103 937__ $$aCRPP-ARTICLE-2004-048
000120103 973__ $$aEPFL$$rREVIEWED$$sPUBLISHED
000120103 980__ $$aARTICLE