On the transport of edge localized mode filaments in the tokamak scrape-off layer

Abstract

Microsecond probe measurements of the electron temperature during the tokamak edge localised mode (ELM) instability show that the peak values significantly exceed those obtained by conventional techniques. The temperatures measured at the plasma facing component (divertor) are around 80% of the initial value (at the pedestal). This challenges the current understanding, where only several percent of the pedestal value are measured at the divertor. Our results imply a negligible energy transfer from the electrons to the ions during the ELM instability, and therefore no associated increase of the ion power loads on the divertor. This observation is supported by the simple analytic free-streaming model, as well as by full kinetic simulations. The energetic ELM ion loads are expected to be one of the main divertor damaging factors; therefore, the obtained results give an optimistic prediction for next generation fusion devices.

Novel concept suppressing plasma heat pulses in a tokamak by fast divertor sweeping

“…There is additionally another limit for the frequency, determined by the fly-time of ions through the swept coil regions. According 51 , . Assuming that it’s 5 keV, the fly-time of Deuterons with the corresponding through the swept coil magnetic field region is s because each ion passes toroidally around and the desired integrates along this path.…”

ITER relevant multi-emissive sheaths at normal magnetic field inclination

“…In accordance with a recent systematic investigation of the ITER W monoblock surface melting and toroidal gap melting limits [54], we shall consider partially mitigated ϵ ⊥ = 0.6 MJ m −2 ELMs that are deposited as square heat flux pulses of q surf = 1.0 GW m −2 at the outer vertical target (OVT) and of q surf = 2.0 GW m −2 at the inner vertical target (IVT) over a duration which corresponds to the 500 µs expected ELM decay time [24]. Given the predicted T ped e = 4.7 keV pedestal temperature for the ITER baseline scenario [55], kinetic simulations of large JET ELMs [56] and conflicting experimental results [57,58] as well as the strong spatiotemporal temperature variations during ELMs, the choice of T e = 500 eV was deemed as reasonable. Finally, the knowledge of q surf , T e allows the calculation of the electron density at the sheath entrance from q surf = γn s.e.…”

The European master of science in nuclear fusion and engineering physics (FUSION-EP): 15 years of experience

“…Results from the the 2-weeks Joint experiment and analysis session at IPP Prague have sometimes been included in regular publications (see e.g. [8,9,10]), a proof that the students can produce a valuable research work at the end of three semesters at FUSION-EP.…”

“…The student's work often contributes to larger scientific proposals resulting in a co-authored publication (e.g. [8][9][10]) or master's thesis collaboration. This additional incentive makes the 'Prague event' one of the highlights of the programme.…”