Overview of results from the MST reversed field pinch experiment

Sarff, J. S.; Almagri, A.F.; Anderson, J. K.; Borchardt, M.; Cappechi, W.; Carmody, D.; Caspary, Kyle; Chapman, B. E.; Hartog, D.J. Den; Duff, J.; Eilerman, S.; Falkowski, Adam; Forest, C. B.; Galante, Matthew; Goetz, J. A.; Holly, D. J.; Koliner, J. J.; Kumar, S. T. A.; Lee, J.D.; Liu, D.; McCollam, K. J.; McGarry, M. B.; Mirnov, V. V.; Morton, L. A.; Munaretto, S.; Nornberg, M. D.; Nonn, P. D.; Oliva, S. P.; Parke, E.; Pueschel, M. J.; Reusch, J.A.; Sauppe, Joshua; Seltzman, Andrew; Sovinec, C. R.; Stone, D.; Theucks, D.; Thomas, Mark A.; Triana, J.C.; Terry, P. W.; Waksman, J.; Whelan, G.C.; Brower, D. L.; Ding, W. X.; Lin, L.; Demers, D. R.; Fimognari, P. J.; Titus, James; Auriemma, F.; Cappello, S.; Franz, P.; Innocente, P.; Lorenzini, R.; Martines, E.; Momo, B.; Piovesan, P.; Puiatti, M. E.; Spolaore, M.; Terranova, D.; Zanca, P.; Давыденко, В. И.; Deichuli, P. P.; Ivanov, A. A.; Polosatkin, S. V.; Stupishin, N.; Spong, D. A.; Craig, D.; Stephens, H.D.; Harvey, R. W.; Cianciosa, M.; Hanson, J.D.; Breǐzman, B. N.; Li, M.; Zheng, Lin

doi:10.1088/0029-5515/55/10/104006

Cited by 17 publications

(17 citation statements)

References 42 publications

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“…Such analysis may be done with other diagnostics (PCI, BES, CECE, FIR, DBS) and may be valid in other fusion devices (RFP [29], stellarators). An example of a study using this knowledge on QC-TEM has been presented.…”

Section: Resultsmentioning

confidence: 99%

Identification of trapped electron modes in frequency fluctuation spectra

Arnichand

Citrin

Hacquin

et al. 2015

Plasma Phys. Control. Fusion

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Abstract.Ion temperature gradient (ITG) and trapped electron modes (TEM) are two important micro-instabilities in the plasma core region of fusion devices (r/a ≤ 0.9). They usually coexist in the same range of spatial scale (around 0.1 < k ⊥ ρ i < 1), which makes their discrimination difficult. To investigate them, one can perform gyrokinetic simulations, transport analysis and phase velocity estimations. In Tore Supra, the identification of trapped electron modes (TEM) is made possible due to measured frequency fluctuation spectra. Indeed, turbulent spectra generally expected to be broad-band can become narrow in case of TEM turbulence, inducing "quasi-coherent" (QC) modes named QC-TEM. Therefore the analysis of frequency fluctuation spectra becomes a possible tool to differentiate TEM from ITG. We have found indications that the TEM can have a QC signature by comparing frequency fluctuation spectra from reflectometry measurements, gyrokinetic simulations and synthetic diagnostic results. Then the scope of the analysis of QC-TEM are discussed and an application is shown, namely transitions between TEM turbulence and MHD fluctuations.

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Section: Resultsmentioning

confidence: 99%

Identification of trapped electron modes in frequency fluctuation spectra

Arnichand

Citrin

Hacquin

et al. 2015

Plasma Phys. Control. Fusion

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“…Furthermore, an unexpected high-frequency (comparable to the geodesic acoustic mode and beta-induced Alfven eigenmode) fishbone has also been observed in JET experiments, with a theoretical interpretation based on a new suitable dispersion relation [12][13][14]. In reversed-field pinch (RFP) configuration, NBI has only recently been applied on the Madison symmetric torus (MST) experiments, with the observation of EP-induced MHD fluctuations [15][16][17]. All the above results provided useful insight into the physics of EPs interacting with global MHD modes.…”

Section: Introductionmentioning

confidence: 99%

Excitation of external kink mode by trapped energetic particles

Guo¹,

Xu²,

Liu

et al. 2016

Nucl. Fusion

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An unstable fishbone-like non-resonant external kink mode (FLEM) is numerically found to be driven by the precessional drift motion of trapped energetic particles (EPs) in both reversed-field pinch (RFP) and tokamak plasmas, even under the ideal wall boundary condition. In the presence of a sufficiently large fraction of trapped energetic ions in high beta plasmas, the FLEM instability may occur. The excitation condition is discussed in detail. The frequency of the FLEM is linked to the precessional drift frequency of EPs, and varies with the plasma flow speed. Therefore, it is usually much higher than that of the typical resistive wall mode (RWM). In general, the growth rate of FLEM does not depend on the wall resistivity. However, the wall position can significantly affect the mode’s property. The drift kinetic effects from thermal particles (mainly due to the transit resonance of passing particles) play a stabilizing role on FLEMs. In the presence of EPs, the FLEM and the RWM can co-exist or even couple to each other, depending on the plasma parameters. The FLEM instabilities in RFP and tokamaks have rather similar physics nature, although certain sub-dominant characters appear differently in the two configurations.

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“…The electron density is in the range n e ˜10 19 m −3 . The mission of KTX is complementary to the existing international RFP facilities [5][6][7][8]. Studies on plasma wall interaction, RFP boundary plasma, transport in different boundary conditions, single helicity (SH) state [9][10][11] are the main physics priorities of KTX.…”

Section: Overview Of Keda Torus Experiments Initial Resultsmentioning

confidence: 99%

Overview of Keda Torus eXperiment initial results

et al. 2017

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The Keda Torus eXperiment (KTX) is a new reversed field pinch (RFP) device at the University of Science and Technology of China. The construction and assembly of KTX, including the vacuum chamber, conducting shell, magnetic field windings, power supply system, active control coils, vacuum pump and data acquisition system, have been completed on August 1, 2015. Immediately following that, the first plasma was obtained on August 15, 2015. Intensive conditioning of the machine is underway to ramp up the plasma current toward its full operation. An active feedback mode control system has been built and has been implemented to control the error field around the vertical gaps of the conducting shell. The pulsed power supply systems of ohmic heating field and toroidal field (TF), using thyristor and energy storage capacitors, have been tested and commissioned. The TF power supply has flexibility in being able to operate with a reversed TF configuration and stable TF configuration. The fundamental diagnostic tools are developed for early KTX operation. Currently, the plasma current is up to 205 kA and the maximum discharge length is 21 ms, approaching to the conducting shell penetration time. Furthermore, typical RFP discharges are being produced with RFP state lasting 2 ms. These initial operation results for KTX are described in detail.

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Overview of results from the MST reversed field pinch experiment

Cited by 17 publications

References 42 publications

Identification of trapped electron modes in frequency fluctuation spectra

Identification of trapped electron modes in frequency fluctuation spectra

Excitation of external kink mode by trapped energetic particles

Overview of Keda Torus eXperiment initial results

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