Speaker
Dr
Nicola Vianello
(Consorzio RFX, Padova, Italy)
Description
Addressing the role of Scrape Off Layer filamentary transport is presently a subject of intense studies in fusion science. Indeed, the broadening of the Scrape Off Layer profiles in high density discharges has been observed in a number of devices. The broadening has been attributed to an increase of the convective contribution to the perpendicular transport [LaBombard, B et al. Phys. Plasmas 8, 2107 (2001)]. Recent observations in AUG and JET L-mode plasma [Carralero, D et al. Phys. Rev. Let. 115, 215002 (2015)] provide support to the idea that the profile broadening is caused by the transition of the filamentary dynamics from sheath-limited to inertial regime. The transition is then due to an increase of effective collisionality [Myra, J. R. et al. Physics of Plasmas 13, 112502 (2006)] and a consequenttial disconnection of the plasma filaments from the target. The experimental results from AUG and JET are not fully supported by observations on devices as MAST and DIII-D. In this context experiments have been performed on the TCV tokamak [Coda, S et al. Nucl. Fus. 53, 104011 (2013)], where the high flexibility in plasma shaping has been used to test the profile broadening against the dependence on the parallel connection length. In a set of L-Mode discharges the flux surface expansion at the outer target was progressively increased between shots, leading to an increase of the parallel connection length from the midplane to the outer target plates by almost a factor of two. In these shots identical density ramps were performed. A clear modification of the target profiles and a modest modification of upstream profiles have been observed. The investigation of profiles and turbulence, as observed from various diagnostics, is presented and correlated with the divertor conditions in terms of detachment and effective collisionality. The data obtained is compared with ASDEX-Upgrade results in terms of effective collisionality and dimensionless parameters.
| Country or International Organization | Italy |
|---|---|
| Paper Number | EX/P8-26 |
Primary author
Dr
Nicola Vianello
(Consorzio RFX, Padova, Italy)
Co-authors
Dr
Anders Henry Nielsen
(Technical University of Denmark, Lingby, Denmark)
Dr
Benoit LABIT
(Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC))
Mr
Bernd Schneider
(Institute for Ion Physics and Applied Physics, University of Innsbruck, Austria)
Dr
Cedric Tsui
(University of California San Diego, CA, USA)
Dr
Christian Theiler
(Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC))
Dr
Codrina Ionita
(Institute for Ion Physics and Applied Physics, University of Innsbruck, Austria)
Dr
Daniel Carralero
(Max-Planck-Institut für Plasmaphysik, Garching, Germany)
Dr
Holger Reimerdes
(Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC))
Prof.
Jens Juul Rasmussen
(Technical University of Denmark, Lingby, Denmark)
Dr
Jens Madsen
(Technical University of Denmark, Lingby, Denmark)
Dr
Jernej Kovacic
(Jožef Stefan Institute, 1000 Ljubljana, Slovenia)
Dr
Jose Boedo
(University of California San Diego, CA, USA)
Mr
Kevin Verhaegh
(York Plasma Institute, University of York, Heslington, UK)
Dr
Monica Spolaore
(Consorzio RFX, Padova, Italy)
Dr
Nicholas Walkden
(Culham Centre for Fusion Energy (CCFE), Culham Science Centre, Abingdon, UK)
Prof.
Roman Schrittwieser
(Institute for Ion Physics and Applied Physics, University of Innsbruck, Austria)
Dr
Scott Allan
(Culham Centre for Fusion Energy (CCFE), Culham Science Centre, Abingdon, UK)
Mr
Stefan Costea
(Institute for Ion Physics and Applied Physics, University of Innsbruck, Austria)
Prof.
Volker Naulin
(Technical University of Denmark, Lingby, Denmark)
Dr
Wouter Vijvers
(FOM Institute DIFFER, Association EURATOM-FOM, Nieuwegein, The Netherlands)
