Feedback control of the sawtooth period through real time control of the ion cyclotron resonance frequency

Lennholm, M; Blackman, T; Chapman, IT; Eriksson, L-G; Graves, JP; Howell, DF; De Baar, M; Calabro, G; Dumont, R; Graham, M; Jachmich, S; Mayoral, ML; Sozzi, C; Stamp, M; Tsalas, M; De Vries, P

dc.contributor.author	Lennholm, M	en
dc.contributor.author	Blackman, T	en
dc.contributor.author	Chapman, IT	en
dc.contributor.author	Eriksson, L-G	en
dc.contributor.author	Graves, JP	en
dc.contributor.author	Howell, DF	en
dc.contributor.author	De Baar, M	en
dc.contributor.author	Calabro, G	en
dc.contributor.author	Dumont, R	en
dc.contributor.author	Graham, M	en
dc.contributor.author	Jachmich, S	en
dc.contributor.author	Mayoral, ML	en
dc.contributor.author	Sozzi, C	en
dc.contributor.author	Stamp, M	en
dc.contributor.author	Tsalas, M	en
dc.contributor.author	De Vries, P	en
dc.date.accessioned	2014-03-01T01:35:45Z
dc.date.available	2014-03-01T01:35:45Z
dc.date.issued	2011	en
dc.identifier.issn	0029-5515	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/21172
dc.subject.classification	Physics, Fluids & Plasmas	en
dc.subject.classification	Physics, Nuclear	en
dc.subject.other	Absorption region	en
dc.subject.other	Closed loop controllers	en
dc.subject.other	Closed loops	en
dc.subject.other	Current drives	en
dc.subject.other	Flux surfaces	en
dc.subject.other	ICRF system	en
dc.subject.other	Ion cyclotron resonance	en
dc.subject.other	Q=1 surface	en
dc.subject.other	Real time	en
dc.subject.other	Reference values	en
dc.subject.other	Sawtooth control	en
dc.subject.other	Sawtooth periods	en
dc.subject.other	Wave frequencies	en
dc.subject.other	Absorption	en
dc.subject.other	Cyclotrons	en
dc.subject.other	Electron cyclotron resonance	en
dc.subject.other	Natural frequencies	en
dc.subject.other	Real time control	en
dc.subject.other	Controllers	en
dc.title	Feedback control of the sawtooth period through real time control of the ion cyclotron resonance frequency	en
heal.type	journalArticle	en
heal.identifier.primary	10.1088/0029-5515/51/7/073032	en
heal.identifier.secondary	http://dx.doi.org/10.1088/0029-5515/51/7/073032	en
heal.identifier.secondary	073032	en
heal.language	English	en
heal.publicationDate	2011	en
heal.abstract	Modification of the sawtooth period through ion cyclotron resonance frequency (ICRF) heating and current drive has been demonstrated in a number of experiments. The effect has been seen to depend critically on the location of the ICRF absorption region with respect to the q = 1 flux surface. Consequently, for ICRF to be a viable tool for sawtooth control, one must be able to control the ICRF absorption location in real time so as to follow variations in the location of the q = 1 surface. To achieve this, the JET ICRF system has been modified to allow the JET real time central controller to control the frequency of the ICRF generators. An algorithm for real time determination of the sawtooth period has been developed and a closed loop controller, which modifies the frequency of the ICRF generators to bring the measured sawtooth period to the desired reference value, has been implemented. This paper shows the first experimental demonstration of closed loop sawtooth period control by real time variation of the ICRF wave frequency. © 2011 IAEA, Vienna.	en
heal.publisher	INT ATOMIC ENERGY AGENCY	en
heal.journalName	Nuclear Fusion	en
dc.identifier.doi	10.1088/0029-5515/51/7/073032	en
dc.identifier.isi	ISI:000291933300034	en
dc.identifier.volume	51	en
dc.identifier.issue	7	en