The effects of electron cyclotron heating and current drive on toroidal Alfven eigenmodes in tokamak plasmas
Dedicated studies performed for toroidal Alfvén eigenmodes (TAEs) in ASDEX-Upgrade (AUG) discharges with monotonic q-profiles have shown that electron cyclotron resonance heating (ECRH) can make TAEs more unstable. In these AUG discharges, energetic ions driving TAEs were obtained by ion cyclotron r...
| Authors: | ; ; ; ; ; ; ; ; |
|---|---|
| Format: | Article |
| Status: | Published version |
| Publication date: | 2018 |
| Country: | España |
| Institution: | Universidad de Sevilla (US) |
| Repository: | idUS. Depósito de Investigación de la Universidad de Sevilla |
| OAI Identifier: | oai:idus.us.es:11441/99691 |
| Online Access: | https://hdl.handle.net/11441/99691 https://doi.org/10.1088/1361-6587/aa90ee |
| Access Level: | Open access |
| Keyword: | Energetic particles Alfvén eigenmodes ECRH ECCD ICRH |
| _version_ | 1878735979201691648 |
|---|---|
| author | Sharapov, S. E. |
| author2 | García Muñoz, Manuel Zeeland, M. A. van Bobkov, B. Classen, I. G. J. Galdón Quiroga, Joaquín González Martín, Juan de Dios Rodríguez Ramos, Mauricio Sanchís Sánchez, Lucía |
| author2_role | author author author author author author author author |
| author_browse | Bobkov, B. Classen, I. G. J. Galdón Quiroga, Joaquín García Muñoz, Manuel González Martín, Juan de Dios Rodríguez Ramos, Mauricio Sanchís Sánchez, Lucía Sharapov, S. E. Zeeland, M. A. van |
| author_facet | Sharapov, S. E. García Muñoz, Manuel Zeeland, M. A. van Bobkov, B. Classen, I. G. J. Galdón Quiroga, Joaquín González Martín, Juan de Dios Rodríguez Ramos, Mauricio Sanchís Sánchez, Lucía |
| author_role | author |
| collection | idUS. Depósito de Investigación de la Universidad de Sevilla |
| description | Dedicated studies performed for toroidal Alfvén eigenmodes (TAEs) in ASDEX-Upgrade (AUG) discharges with monotonic q-profiles have shown that electron cyclotron resonance heating (ECRH) can make TAEs more unstable. In these AUG discharges, energetic ions driving TAEs were obtained by ion cyclotron resonance heating (ICRH). It was found that off-axis ECRH facilitated TAE instability, with TAEs appearing and disappearing on timescales of a few milliseconds when the ECRH power was switched on and off. On-axis ECRH had a much weaker effect on TAEs, and in AUG discharges performed with co- and counter-current electron cyclotron current drive (ECCD), the effects of ECCD were found to be similar to those of ECRH. Fast ion distributions produced by ICRH were computed with the PION and SELFO codes. A significant increase in Te caused by ECRH applied off-axis is found to increase the fast ion slowing-down time and fast ion pressure causing a significant increase in the TAE drive by ICRH-accelerated ions. TAE stability calculations show that the rise in Te causes also an increase in TAE radiative damping and thermal ion Landau damping, but to a lesser extent than the fast ion drive. As a result of the competition between larger drive and damping effects caused by ECRH, TAEs become more unstable. It is concluded, that although ECRH effects on AE stability in present-day experiments may be quite significant, they are determined by the changes in the plasma profiles and are not particularly ECRH specific. |
| eu_rights_str_mv | openAccess |
| format | article |
| id | ES_86a2df14bbddaf5eadcdadf0ba80da5e |
| institution | Universidad de Sevilla (US) |
| instname_str | Universidad de Sevilla (US) |
| network_acronym_str | ES |
| network_name_str | España |
| oai_identifier_str | oai:idus.us.es:11441/99691 |
| publishDate | 2018 |
| publishDateSort | 2018 |
| publisher | IOP Publishing |
| publisherStr | IOP Publishing |
| reponame_str | idUS. Depósito de Investigación de la Universidad de Sevilla |
| spelling | The effects of electron cyclotron heating and current drive on toroidal Alfven eigenmodes in tokamak plasmas Sharapov, S. E. García Muñoz, Manuel Zeeland, M. A. van Bobkov, B. Classen, I. G. J. Galdón Quiroga, Joaquín González Martín, Juan de Dios Rodríguez Ramos, Mauricio Sanchís Sánchez, Lucía Energetic particles Alfvén eigenmodes ECRH ECCD ICRH Dedicated studies performed for toroidal Alfvén eigenmodes (TAEs) in ASDEX-Upgrade (AUG) discharges with monotonic q-profiles have shown that electron cyclotron resonance heating (ECRH) can make TAEs more unstable. In these AUG discharges, energetic ions driving TAEs were obtained by ion cyclotron resonance heating (ICRH). It was found that off-axis ECRH facilitated TAE instability, with TAEs appearing and disappearing on timescales of a few milliseconds when the ECRH power was switched on and off. On-axis ECRH had a much weaker effect on TAEs, and in AUG discharges performed with co- and counter-current electron cyclotron current drive (ECCD), the effects of ECCD were found to be similar to those of ECRH. Fast ion distributions produced by ICRH were computed with the PION and SELFO codes. A significant increase in Te caused by ECRH applied off-axis is found to increase the fast ion slowing-down time and fast ion pressure causing a significant increase in the TAE drive by ICRH-accelerated ions. TAE stability calculations show that the rise in Te causes also an increase in TAE radiative damping and thermal ion Landau damping, but to a lesser extent than the fast ion drive. As a result of the competition between larger drive and damping effects caused by ECRH, TAEs become more unstable. It is concluded, that although ECRH effects on AE stability in present-day experiments may be quite significant, they are determined by the changes in the plasma profiles and are not particularly ECRH specific. EURATOM 633053 RCUK Energy Programme P012450/1 IOP Publishing https://hdl.handle.net/11441/99691 https://doi.org/10.1088/1361-6587/aa90ee |
| spellingShingle | The effects of electron cyclotron heating and current drive on toroidal Alfven eigenmodes in tokamak plasmas Sharapov, S. E. Energetic particles Alfvén eigenmodes ECRH ECCD ICRH |
| status_str | publishedVersion |
| title | The effects of electron cyclotron heating and current drive on toroidal Alfven eigenmodes in tokamak plasmas |
| title_full | The effects of electron cyclotron heating and current drive on toroidal Alfven eigenmodes in tokamak plasmas |
| title_fullStr | The effects of electron cyclotron heating and current drive on toroidal Alfven eigenmodes in tokamak plasmas |
| title_full_unstemmed | The effects of electron cyclotron heating and current drive on toroidal Alfven eigenmodes in tokamak plasmas |
| title_short | The effects of electron cyclotron heating and current drive on toroidal Alfven eigenmodes in tokamak plasmas |
| title_sort | The effects of electron cyclotron heating and current drive on toroidal Alfven eigenmodes in tokamak plasmas |
| topic | Energetic particles Alfvén eigenmodes ECRH ECCD ICRH |
| topic_facet | Energetic particles Alfvén eigenmodes ECRH ECCD ICRH |
| url | https://hdl.handle.net/11441/99691 https://doi.org/10.1088/1361-6587/aa90ee |