Theoretical analysis of ICRF heating in JET DT plasmas

Abstract

A number of experiments with heating of deuterium-tritium (D-T) plasmas using waves in the ion cyclotron range of frequencies (ICRF) have been carried out at the Joint European Torus (JET). The results of these experiments have been analysed by comparing experimentally measured quantities with results of numerical simulations. In particular, four scenarios have been examined: (1) heating of minority (~5−20%) deuterons at the fundamental ion cyclotron frequency, ω ω = cD ; (2) second harmonic heating of tritium, ω ω = 2 cT ; (3) fundamental minority heating of 3 He with a few percent of 3He, and (4) second harmonic heating of deuterium, ω ω = 2 cD . An important aim of the analysis is to assess if the present understanding of the ICRF physics is adequate for predicting the performance of ICRF in D-T plasmas. In general good agreement between experimental results and simulations is found which increases the confidence in predictions of the impact of ICRF heating in future reactors. However, when a relatively high deuterium concentration was used in the ω ω = cD scenario, discrepancies are observed. In order to increase confidence in the simulations, we have studied the sensitivity of the simulation results to various plasma parameters.

Experimental investigation of ion cyclotron range of frequencies heating scenarios for ITER's half-field hydrogen phase performed in JET

“…While the ICRF scenarios for the full-field DT phase of ITER have already been extensively explored in the past (see [30][31][32][33][34] and references therein), the heating schemes for the non-active half-field phase in hydrogen plasmas were not yet investigated carefully in large tokamaks. Recently, JET experiments have been designed to test some of these scenarios and numerical efforts for assessing their performance under ITER conditions have been put forward [35][36][37].…”

Bulk ion heating with ICRF waves in tokamaks

“…in the plasma ramp up phase when the fast tritium tail ions may become too energetic for efficient bulk ion heating [1][2][3]. The bulk ion heating capabilities of the ω = ω( 3 He) = 2 ω T scenario were successfully demonstrated in the 1990's in the flagship deuterium-tritium (D-T) campaigns in TFTR [4,5] and in JET [6][7][8][9][10][11][12]. Subsequently, 3 He minority heating has become a standard tool on JET to provide bulk ion heating without net toroidal torque for ITER physics studies, c.f.…”

Chapter 5: Burning Plasma Studies at JET

“…and ICRH techniques capable of accelerating hydrogen isotopes H, D, T, and 3 He up to the MeV energy range. [6][7][8] A population of energetic 4 He ions can be obtained in D-T fusion reactions with quite significant values of the fast ion density and energy contents. 9,10 It is also possible to accelerate a population of 4 He ions up to the MeV energy range with NBI plus ICRH technique in radiation-free helium plasma.…”

“…[6][7][8]11,13 ICRH is used for heating of both electrons and ions, depending on the ratio between the critical energy and the tail temperature of ICRH-accelerated ions. In this chapter, only ICRH experiments generating temperatures of energetic ion tail in the MeV energy range are considered, since these ions can mimic fusion ions of a burning plasma.…”