Centre de Recherches en Physique des Plasmas EPFL, Association Euratom-Fdration Suisse, Lausanne, Switzerland S. Coda, 24 th IAEA Fusion Energy Conference, OV/4-4, San Diego, 9 October 2012 Overview of recent and current research on the TCV tokamak for the TCV team* S. Coda *including collaborating institutions: S. Coda, 24 th IAEA Fusion Energy Conference, OV/4-4, San Diego, 9 October 2012 Overview of research in TCV 2 TCV parameters and capabilities Scientific mission of the TCV program TCV science ELM control by ECRH and by plasma shaping Physics of the snowflake divertor New insights into energy confinement Pulse optimization by r/t control and r/t simulations Integrated MHD instability control Summary and outlook Outline S. Coda, 24 th IAEA Fusion Energy Conference, OV/4-4, San Diego, 9 October 2012 Overview of research in TCV 3 TCV R = 0.88 m, a = 0.25 m I p < 1 MA, B T < 1.54 T < 2.8, -0.6 < < MW ECRH power, 7 steerable launchers 4 2 S. Coda, 24 th IAEA Fusion Energy Conference, OV/4-4, San Diego, 9 October 2012 Overview of research in TCV 4 Study plasma and fusion science for ITER and next step flexibility and proven ability to test new theories quickly Develop and test techniques for reactor operation strong emphasis on real-time control, particularly with event triggers TCV mission S. Coda, 24 th IAEA Fusion Energy Conference, OV/4-4, San Diego, 9 October 2012 Overview of research in TCV 5 Outline TCV parameters and capabilities Scientific mission of the TCV program TCV science ELM control by ECRH and by plasma shaping Physics of the snowflake divertor New insights into energy confinement Pulse optimization by r/t control and r/t simulations Integrated MHD instability control Summary and outlook S. Coda, 24 th IAEA Fusion Energy Conference, OV/4-4, San Diego, 9 October 2012 Overview of research in TCV 6 Local ECRH in pedestal influences ELMs J.X. Rossel et al, NF 52, (2012) X2 Resonances X3 =0.97 =0.93 =0.85 As power deposition moves towards plasma boundary, ELMs become smaller and more frequent (good!) even though less power is absorbed simple scaling of type-I ELMs (frequency increases with power) is incomplete: power deposition location must play a role too S. Coda, 24 th IAEA Fusion Energy Conference, OV/4-4, San Diego, 9 October 2012 Overview of research in TCV 7 ELM detected power cut for a set time power restored to trigger next ELM ELM period still governed by energy input (longer cut less energy longer period), but r/t control regularizes it Pacing: r/t ECRH steadies ELM period standard deviation of period cw heating pacing S. Coda, 24 th IAEA Fusion Energy Conference, OV/4-4, San Diego, 9 October 2012 Overview of research in TCV 8 ECRH triggers individual ELMs independently of preceding ones For a given trigger sequence, the resulting ELM sequence is highly reproducible see also B.P. Duval et al, EX/1-2 (poster session P2, now) S. Coda, 24 th IAEA Fusion Energy Conference, OV/4-4, San Diego, 9 October 2012 Overview of research in TCV 9 Shaping influences ELMs: smaller, more frequent at negative triangularity A. Pochelon et al, to be published in Plasma and Fusion Research (2012) S. Coda, 24 th IAEA Fusion Energy Conference, OV/4-4, San Diego, 9 October 2012 Overview of research in TCV 10 Outline TCV parameters and capabilities Scientific mission of the TCV program TCV science ELM control by ECRH and by plasma shaping Physics of the snowflake divertor New insights into energy confinement Pulse optimization by r/t control and r/t simulations Integrated MHD instability control Summary and outlook S. Coda, 24 th IAEA Fusion Energy Conference, OV/4-4, San Diego, 9 October 2012 Overview of research in TCV 11 The snowflake divertor: an advanced configuration proven to lessen wall loads = (distance between X-points) (minor radius) Merging of 2 X-points B =0 4 strike points Benefits: doubling of strike points + flux expansion On TCV, average ELM energy release reduced too S. Coda, 24 th IAEA Fusion Energy Conference, OV/4-4, San Diego, 9 October 2012 Overview of research in TCV 12 Lower strike point activated for