Coelho, R.

Madsen, Jens

Magnussen, Michael Løiten

Naulin, Volker

Nielsen, Anders Henry

Olsen, Jeppe Miki Busk

Rasmussen, Jens Juul

Thrysøe, Alexander Simon

Tophøj, Laust Emil Hjerrild

Online Research Database In Technology

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Downloaded from orbit.dtu.dk on: Dec 18, 2017Simulations of filamentary transport in the SOL and estimations of the powerdeposition profileRasmussen, Jens Juul; Nielsen, Anders Henry; Madsen, Jens; Naulin, Volker; Olsen, Jeppe Miki Busk;Magnussen, Michael Løiten; Thrysøe, Alexander Simon; Tophøj, Laust Emil Hjerrild; Coelho, R.Publication date:2016Document VersionPeer reviewed versionLink back to DTU OrbitCitation (APA):Rasmussen, J. J., Nielsen, A. H., Madsen, J., Naulin, V., Olsen, J. M. B., Magnussen, M. L., ... Coelho, R.(2016). Simulations of filamentary transport in the SOL and estimations of the power deposition profile. Abstractfrom 21st EU-US Transport Task Force Meeting, Leysin, Switzerland.21st EU-US Transport Task Force Meeeting, Leysin, 5-8 September 2016  Simulations of filamentary transport in the SOL and estimations of the power deposition  profile  J. Juul Rasmussen1, A. H. Nielsen1, J. Madsen1, V. Naulin1, J.M.B. Olsen1, M. Løiten1, A.S Thrysøe1, L. Tophøj1, and R. Coelho2  1DTU Physics, Technical University of Denmark, Kgs. Lyngby, Denmark  2Instituto de Plasmas e Fusão Nuclear, University of Lisboa, Portugal  Corresponding author: Jens Juul Rasmussen       Email: jjra@fysik.dtu.dk  The transport in the edge region and through the scrape-off-layer (SOL) at the outboard mid-plane of magnetically confined toroidal plasmas is known to be strongly intermittent and dominated by filamentary structures of enhanced plasma pressure – plasma blobs. These structures are generated in the edge region and propagate through the SOL with velocities up to a few percent of the ion acoustic speed. They play a significant role in setting up the plasma profiles in the SOL and for the power deposition profiles. We have investigated the transport dynamics, the ensuing density and pressure profiles in the SOL, and estimated power depositions on plasma facing components by ap-plying the HESEL code. HESEL is an energy conserving four-field Braginskii model governing the dynamical evolution of generalized vorticity, density, elec-tron, and ion pressures [1]. The parallel dynamics in the SOL is parametrized and different divertor conditions - attached or detached - are mimicked by applying sheath boundary condi-tions to either the full potential field or only its profile, re-spectively. This significantly affects the evolution of the plasma blobs and thus the transport of energy and particles through the SOL. We further observe an asymmetry between the ion and electron temperature both in the blob structures and in the background SOL plasma. Ion temperatures are typical 2-4 times higher than the electron temperature, which is a result of different parallel and perpendicular dissipation rates. The power deposition profile at the divertor is obtained by mapping the mid-plane pressure profiles to the divertor region along the magnetic field lines [2], see figure (for the “attached” case) where the traces of the individual blob structures are clearly identified. We have investigated different L-mode scenarios including cases with high upstream SOL density – the so-called “shoulder” formation - recently characterized in JET and ASDEX Upgrade [3]. Within the present model we observe  - for the same divertor condi-tion – the formation of a ‘shoulder’ in the density profile by increasing the connection length, thus decreasing the efficiency of the SOL ability to remove plasma from the outboard midplane.  HESEL is embedded into a Kepler workflow developed within the EUROfusion Integrated Model-ling framework [2]. This consists of a workflow allowing access to experimental Langmuir probe data as well as discharge parameters.  [1] J. Madsen et al. Phys. Plasmas 23, 032306 (2016). [2] A.H. Nielsen et al. 42nd EPS Conference on Plasma Physics, Lisbon, Portugal 2015, P1.105, ECA Vol. 39E. [3] D. Carralero et al. J. Nucl. Mat. 463, 123, (2015); Phys. Rev. Lett. 115, 215002 (2015). -----------------------------------------------------------------------------------------------------------------------------------------------------------  Preference:  ☐X  Oral   in session:   Understanding power decay length in the SOL   Power deposition at divertor (MJ/sm2)    

Simulations of filamentary transport in the SOL and estimations of the power deposition profile

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Simulations of filamentary transport in the SOL and estimations of the power deposition profile

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