Beam-driven ion-cyclotron modes in the scrape-off layer of a field-reversed configuration

Abstract

In the scrape-off-layer (SOL) of a field-reversed configuration, neutral beam injection can drive modes in the vicinity of the ion-cyclotron frequency. Depending on their properties, these modes can have differing macroscopic effects on the plasma. Using particle-in-cell simulations and semi-analytical methods, this work examines the properties of the various categories of ion-cyclotron modes that can be excited in the SOL environment, taking an ion beta of 10%. Propagation angle and beam injection angle are scanned from 0° to 90° with respect to the external magnetic field. The linear physics of these modes is treated foremost, but the non-linear physics, particularly regarding ion acceleration with consequences for plasma stability and fusion reactivity, is also examined. Near perpendicular propagation and beam injection are found to give the greatest fusion enhancement. This result derives from an extension of wakefield acceleration physics to the case of ion acceleration in a magnetized fusion plasma. The non-linear physics of this regime is thus given particular attention.

First measurements of p11B fusion in a magnetically confined plasma

“…This will include developing techniques to further increase the fusion gain via alpha channeling 27 , profile tuning, phase space engineering, fusion product current drive 14 , and the exploitation of collective beam-induced heating 12 , 13 . It will also, as described above, involve studying the interplay of fast ion diffusion on the fusion rate in the presence of resonant peaks, something that can’t be reproduced with fusion in a DD or DT plasma or in p 11 B beam-target fusion.…”

“…The magnetically confined plasma is a much richer environment, allowing for studies of collective effects on the fusion reaction rate. For example, recent work on wave-particle interaction in the FRC indicate a natural boost to the fusion output due to a beam-driven wave 12 , 13 . The effects of the resonances in the p 11 B cross section in the presence of high-energy tails and non-thermal distributions on the fusion rate can also be explored.…”

Demonstration of aneutronic p-11B reaction in a magnetic confinement device

“…It was reported that thermal p-11 B reactor could be realized including the kinetic effect and using the newly measured p-11 B cross section [32]. Rostoker and his teams [33] have advocated the use of beam-driven fusion to help fusion reactions not solely dependent on the plasma temperature, by creating long tail distributions that are more reactive [34,35]. In pursuit of this goal, TAE Technologies is advancing the concepts originally proposed by Tajima and Binderbauer [33] with the beam-driven, field reversed configuration.…”

Identification of core ion cyclotron instabilities on HL-2A tokamak

“…Through comparing the detected frequency and f ci , the ICE was located around the outer edge midplane of the plasma and was believed to be excited by deeply trapped alpha particles reaching the plasma edge. Subsequently, a significant amount of research has been conducted on ICE in tokamaks, including JT-60U [12][13][14][15], KSTAR [16][17][18], TUMAN-3M [19,20], ASDEX-U [21][22][23][24][25], EAST [26], START [27], MAST [28], JET [29] NSTX/NSTX-U [30,31] and DIII-D [32][33][34][35], stellarators, including W7-AS [36] and LHD [37][38][39][40], and field reversed configuration C-2U device [41,42]. ICE is located around both the edge and the core of the plasma, and is destabilized by EP from D-T and D-D fusion reaction, neutral beam injection (NBI), and plasma heating in the ion cyclotron range of frequencies.…”