| 1. |
- Hellsten, Torbjörn
(författare)
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Rotation Driven by Rectified RF-sheath Potentials and Spatial Dispersion
- 2009
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Ingår i: RADIO FREQUENCY POWER IN PLASMAS. - : AIP. - 9780735407534 ; , s. 625-628
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Konferensbidrag (refereegranskat)abstract
- Plasma rotation is of interest for improving confinement and stabilising plasma. Effects from fast particles with broad orbits can only partly explain the changes in the rotation profiles during ICRH. The effect on wave-particle interaction of a finite poloidal mode number is discussed and two new RF-mechanisms are proposed: Co-current torque caused by sputtering by rectified RF-sheath potentials and transport of momentum due to spatial dispersion. The latter effect affects the RF-current drive, in particular, in conjunction with mode conversion.
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| 2. |
- Höök, Josef, et al.
(författare)
-
Adaptive delta f Monte Carlo Method for Simulation of RF-heating and Transport in Fusion Plasmas
- 2009
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Ingår i: Radio Frequency Power in Plasmas. - : American Institute of Physics (AIP). - 9780735407534 ; , s. 589-592
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Konferensbidrag (refereegranskat)abstract
- Essential for modeling heating and transport of fusion plasma is determining the distribution function of the plasma species. Characteristic for RF-heating is creation of particle distributions with a high energy tail. In the high energy region the deviation from a Maxwellian distribution is large while in the low energy region the distribution is close to a Maxwellian due to the velocity dependency of the collision frequency. Because of geometry and orbit topology Monte Carlo methods are frequently used. To avoid simulating the thermal part, delta f methods are beneficial. Here we present a new delta f Monte Carlo method with an adaptive scheme for reducing the total variance and sources, suitable for calculating the distribution function for RF-heating
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| 3. |
- Mayoral, M. -L, et al.
(författare)
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Overview of Recent Results on Heating and Current Drive in the JET tokamak
- 2009
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Ingår i: RADIO FREQUENCY POWER IN PLASMAS. - : AIP. - 9780735407534 ; , s. 39-46
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Konferensbidrag (refereegranskat)abstract
- In this paper, significant results in the heating and current drive domains obtained at JET in the past few years following systems upgrade and dedicated experimental time, will be reviewed. Firstly, an overview of the new Ion Cyclotron Resonance Frequency (ICRF) heating capabilities will be presented i.e. results from the ITER-Like ICRF antenna (ILA), the use of External Conjugate-T and 3dB hybrid couplers to increase the ICRF power during ELMy H-mode, Furthermore, experiments to study the influence of the phasing of the ICRF antenna on power absorption and coupling will be described. Looking at Low Hybrid (I-H) issues for ITER, the effect of the location of gas injection on the LH coupling improvement at large launcher-separatrix distances will be discussed as the possibility to operate at ITER-relevant power densities. Experiments to characterise the LH power losses in the Scrape-Off-Layer (SOL) and to determine the LH wave absorption and current drive using power modulation will be shown. Finally, plasma rotation studies in the presence of ICRF heating with standard and enhanced JET toroidal field ripple will be presented.
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