B Chapman R O Dendy S C Chapman K G McClements R Ochoukov
Observations have recently been made of ion cyclotron emission (ICE) that originates from the core plasma in the DIII-D and ASDEX-Upgrade tokamaks. In some of these cases, the ICE spectral peaks correspond to the local cyclotron harmonic frequencies of fusion-born ions close to the magnetic axis. This is in contrast to the hitherto usual spatial lo…
PreprintA. R. Jackson A. S. Jacobsen K. G. McClements C. A. Michael M. Cecconello
The efficient confinement of fast ions is crucial to the development of a fusion power plant. Sawtooth crashes are a manifestation of an internal kink instability, which can severely degrade this confinement. The effect of these on a fast ion population can be investigated using fast-ion deuterium-alpha (FIDA) spectroscopy, where charge exchange…
Preprint PublishedR O Dendy B Chapman G S Yun S C Chapman K G McClements S G Thatipamula M H Kim A Zalzali
Intense suprathermal radiation, with spectral peaks at multiple harmonics of the deuteron cyclotron frequency, is detected from the outer midplane edge of KSTAR deuterium plasmas that are heated by tangential neutral beam injection (NBI) of 100keV deuterons. We identify how this deuterium ion cyclotron emission (ICE) is generated, and distinguish t…
Preprint PublishedN. Vianello D. Carralero C. K. Tsui V. Naulin M. Agostini J. Boedo B. Labit C. Theiler D. Aguiam S. Allan M. Bernert S. Costea I. Cziegler H. De Oliveira J. Galdon-Quiroga G. Grenfell A. Hakola C. Ionita H. Isliker A. Karpushov J. Kovacic B. Lipschultz R. Mauriozio K. McClements F. Militello J. Olsen J. J. Rasmussen T. Ravensbergen H. Reimerdes B. Schneider R. Schrittwieser M. Spolaore K. Verhaegh J. Vicente N. Walkden W. Zhang E. Wolfrum the ASDEX Upgrade Team the TCV team the EUROfusion MST1 Team
A detailed cross-device investigation on the role of filamentary dynamics in high density regimes has been performed within the EUROfusion framework comparing ASDEX-Upgrade (AUG) and TCV tokamaks. Both devices have run density ramp experiments at different levels of plasma current, keeping toroidal field or q95 constant in order to disentangle the …
Preprint PublishedR O Dendy B Chapman S C Chapman K G McClements G S Yun S G Thatipamula M H Kim
During ELM crashes in deuterium plasmas in the KSTAR tokamak, the emitted electromagnetic radiation includes features with sharp spectral structure in the frequency range up to ~900MHz. Cases where the spectral peaks below ~500MHz correspond to proton cyclotron harmonics at the outer midplane edge are explained (B Chapman et al., Nucl.…
Preprint PublishedJ.F. Rivero-Rodriguez M. Garcia-Muñoz R. Martin J. Galdon-Quiroga J. Ayllon-Guerola R. J. Akers J. Buchanan D. Croft D. Garcia-Vallejo J. Gonzalez-Martin D. Harvey K.G. McClements M. Rodriguez-Ramos L. Sanchis-Sanchez the MAST Upgrade Team
The design and unique feature of the first MAST-U fast-ion loss detector (FILD) [M. Garcia-Muñoz, Rev. Sci. Instrum 80, 053503 (2009)] is presented here. The MAST-U FILD head is mounted on an axially and angularly actuated mechanism that makes…
Preprint PublishedR. Ochoukov V. Bobkov H. Faugel M. García-Muñoz B. Geiger D. Moseev K. G. McClements S. Nielsen P. Schneider M. Weiland J.-M. Noterdaeme ASDEX Upgrade Team MST1 Team
Ion cyclotron emission (ICE) is a commonly observed feature of magnetized toroidal plasmas in the presence of fast ions. It is generally agreed that this emission is caused by a strongly inverted (in the velocity space) population of confined fast ions originating from either neutral beam injection (NBI), fusion reactions, or acceleration by waves …
Preprint PublishedB Chapman R O Dendy S C Chapman K G McClements G S Yun S G Thatipamula M H Kim
Intense bursts of suprathermal radiation, with spectral peaks at frequencies corresponding to the deuteron cyclotron frequency in the outer midplane edge region, are often detected from deuterium plasmas in the KSTAR tokamak that are heated by tangential neutral beam injection (NBI) of deuterons at 100 keV. Identifying the physical process by wh…
Preprint PublishedJ.Galdon-Quiroga M.Garcia-Munoz S.Sharapov L.Sanchis-Sanchez L.Chen M.Dunne J.Gonzalez-Martin M.Hoelz A.S.Jacobsen K.G.McClements M.Nocente F.Orain J.F.Rivero-Rodriguez D.A.Ryan M.Salewski P.Schneider A.Snicker W.Suttrop Y.Todo M.A.Van Zeeland E.Viezzer M.Willensdorfer D.Zarzoso F.Zonca The ASDEX Upgrade Team MST1 Team
An edge resonant transport layer has been found to explain many aspects of fast-ion confinement under symmetry breaking 3D edge perturbations, such as edge localized modes (ELMs) and externally applied magnetic perturbations (MPs). Experimental measurements in the ASDEX Upgrade (AUG) tokamak show that fast-ion losses in the presence of symmetry bre…
Preprint PublishedK.G. McClements
Detailed in situ studies of magnetic reconnection and particle acceleration, which play a crucial role in the release and redistribution of energy in solar flares, can be performed in tokamak plasmas under conditions resembling those of the flaring solar corona. Recent measurements and modelling of fast particle production during reconnection event…
Preprint Published