Observation of multi-channel non-local transport in J-TEXT plasmas

Abstract

In cold pulse experiments in J-TEXT, not only are rapid electron temperature increases in core observed, but also steep rises of inner density are found. Moreover, some evidence of acceleration of the core toroidal rotation is also observed during the non-local transport process of electron temperature. These new findings of cold pulse experiments in J-TEXT suggest that turbulence spreading is possible mechanism for the non-local transport dynamics.

Observation of non-local effects in ion transport channel in J-TEXT plasmas

“…In a nutshell, in most of the previous experimental research, the NLT phenomenon in the cold pulse experiment has only reported and focused on the electron heat transport channel. However, our research results in J-TEXT show that NLT effects also exist in particle transport channel [17]. The rotation or momentum transport also has some possible NLT response in the cold pulse experiment [17].…”

“…However, our research results in J-TEXT show that NLT effects also exist in particle transport channel [17]. The rotation or momentum transport also has some possible NLT response in the cold pulse experiment [17]. Recently, the temporal resolution of the diagnostic systems for ion temperature measurement in J-TEXT is upgraded to millisecond level, which provides us with the capability to investigate the dynamic response of ion transport channel in the cold pulse experiment.…”

“…A fast increase of the central electron temperature caused by the edge cooling in Ohmic heating (OH) plasmas, the so-called non-local heat transport (NLT) [1] is one of these challenging issues. NLT was first observed in the TEXT tokamak 23 years ago, and in many fusion devices afterwards (TFTR [2], RTP [3], ASDEX UPGRAGE [4], Tore Supra [5], JET [6], LHD [7][8][9], HL-2A [10][11][12], Alcator C-Mod [13][14][15], KSTAR [16], J-TEXT [17], and EAST [18]). NLT phenomenon shows that the limitation of transport theory based on traditional local transport model.…”

“…A fast increase of the central electron temperature caused by the edge cooling in Ohmic heating (OH) plasmas, the so-called non-local heat transport (NLT) [1] is one of these challenging issues. NLT was first observed in the TEXT tokamak 23 years ago, and in many fusion devices afterwards (TFTR [2], RTP [3], ASDEX UPGRAGE [4], Tore Supra [5], JET [6], LHD [7][8][9], HL-2A a See Liang et al 2019 (https://doi.org/10.1088/1741-4326/ab1a72) for the J-TEXT team [10][11][12], Alcator C-Mod [13][14][15], KSTAR [16], J-TEXT [17], EAST [18], and DIII-D [19]). Here, we emphasize that the term 'non-local transport' in this paper represent the experimental phenomenon of rapid coupling between edge cold pulse and core parameters.…”

Long radial coherence of electron temperature fluctuations in non-local transport in HL-2A plasmas

“…One of the perplexing phenomena observed and extensively studied worldwide is non-local transport, which has been investigated in various tokamaks (TFTR, [1] TEXT [2] /J-TEXT, [3] , RTP, [4,5] HL-2A, [6] Alcator C-mod, [7] KSTAR, [8] EAST, [9] Tore Supra, [10] JET, [11] AUG, [12] DIII-D [13] ) and stellerators(W7-AS, [14] LHD [15] ). These experiments have consistently revealed a peculiar long-range transient temperature response triggered by pulsed interventions.…”