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Self-consistent simulations of ICRH in ITB plasmas
KTH, Tidigare Institutioner                               , Alfvénlaboratoriet.
KTH, Tidigare Institutioner                               , Alfvénlaboratoriet.
KTH, Tidigare Institutioner                               , Alfvénlaboratoriet.
2001 (engelsk)Inngår i: AIP Conf. Proc.: October 29, 2001, 2001, s. 414-417Konferansepaper, Publicerat paper (Annet vitenskapelig)
Abstract [en]

The RF power partition and power deposition on resonant ion species during ICRH depend strongly on the distribution functions of the heated ions. The distribution functions in turn depend on RF interactions and Coulomb collisions with the background plasma. It has previously been found that the finite ion orbit width, as well as the RF induced transport of resonant ions, are important for describing the distribution functions. This is particularly important in ITB plasmas, where low central current density results in broad orbits. To simulate ICRH in ITB plasmas the SELFO code has been upgraded to self-consistently calculate the wave field and the distribution functions of several ion species, including beam injected ions. Simulations of hydrogen minority heating of a deuterium, JET-like, ITB plasma have been made for different antenna phasings, with and without NBI. The distribution functions of both hydrogen and deuterium have been simulated. Finite orbit width and RF induced particle transport effects are shown to have a large impact on the partition of RF power absorption between hydrogen and deuterium, and thereby on the power transfer to the background.

sted, utgiver, år, opplag, sider
2001. s. 414-417
Emneord [en]
plasma radiofrequency heating, cyclotron resonance, ions, collision processes, electromagnetic wave absorption, Monte Carlo methods, antennas in plasma
HSV kategori
Identifikatorer
URN: urn:nbn:se:kth:diva-12706DOI: 10.1063/1.1424221OAI: oai:DiVA.org:kth-12706DiVA, id: diva2:318164
Konferanse
RADIO FREQUENCY POWER IN PLASMAS:14th Topical Conference
Merknad
QC 20100506Tilgjengelig fra: 2010-05-06 Laget: 2010-05-06 Sist oppdatert: 2010-07-14bibliografisk kontrollert
Inngår i avhandling
1. Fast wave heating and current drive in tokamaks
Åpne denne publikasjonen i ny fane eller vindu >>Fast wave heating and current drive in tokamaks
2005 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

This thesis concerns heating and current drive in tokamak plasmas using the fast magnetosonic wave in the ion cyclotron range of frequencies. Fast wave heating is a versatile heating method for thermonuclear fusion plasmas and can provide both ion and electron heating and non-inductive current drive. Predicting and interpreting realistic heating scenarios is however difficult due to the coupled evolution of the cyclotron resonant ion velocity distributions and the wave field. The SELFO code, which solves the coupled wave equation and Fokker-Planck equation for cyclotron resonant ion species in a self-consistent manner, has been upgraded to allow the study of more advanced fast wave heating and current drive scenarios in present day experiments and in preparation for the ITER tokamak.

Theoretical and experimental studies related to fast wave heating and current drive with emphasis on fast ion effects are presented. Analysis of minority ion cyclotron current drive in ITER indicates that the use of a hydrogen minority rather than the proposed helium-3 minority results in substantially more efficient current drive. The parasitic losses of power to fusion born alpha particles and beam injected ions are concluded to be acceptably low. Experiments performed at the JET tokamak on polychromatic ion cyclotron resonance heating and on fast wave electron current drive are presented and analysed. Polychromatic heating is demonstrated to increase the bulk plasma ion to electron heating ratio, in line with theoretical expectations, but the fast wave electron current drive is found to be severely degraded by parasitic power losses outside of the plasma. A theoretical analysis of parasitic power losses at radio frequency antennas indicates that the losses can be significantly increased in scenarios with low wave damping and with narrow antenna spectra, such as in electron current drive scenarios.

sted, utgiver, år, opplag, sider
Stockholm: KTH, 2005. s. xiv, 42
Emneord
Tokamak, JET, ITER, thermonuclear fusion, fast wave, heating, current drive, ion cyclotron resonance, polychromatic, finite orbit widths, RF-induced transport, neutral beam injection, fusion born alpha particles, magnetosonic eigenmodes, parasitic absorption, modelling, weighted Monte Carlo scheme, Fysik
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-118 (URN)91-7283-954-6 (ISBN)
Disputas
2005-02-08, Kollegiesalen, Valhallavägen 79, Stockholm, 10:00 (engelsk)
Opponent
Veileder
Merknad
QC 20100506Tilgjengelig fra: 2005-02-04 Laget: 2005-02-04 Sist oppdatert: 2011-02-24bibliografisk kontrollert

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