Showing 1 - 8 of 8 Journals Results
2021
UKAEA-CCFE-PR(21)09
B. C. G. Reman R. O. Dendy T. Akiyama S. C. Chapman J. W. S. Cook H. Igami S. Inagaki K. Saito M.H. Kim S.G. Thatipamula G. S. Yun
Ion cyclotron emission (ICE) driven by perpendicular neutral beam-injected (NBI) deuterons, together with the distinctive ICE driven by tangential NBI, have been observed from heliotron-stellarator plasmas in the Large Helical Device (LHD). Radio frequency radiation in the lower hybrid range has also been observed, with frequency dependent on plasm…
Preprint2020
UKAEA-CCFE-PR(21)48
B. C. G. Reman R. O. Dendy T. Akiyama M. Salewski S.C. Chapman J. W. S. Cook H. Igami S. Inagaki K. Saito R.Seki G. S. Yun
During bursty MHD events, transient ion cyclotron emission (ICE) is observed from deuterium plasmas in the Large Helical Device (LHD) heliotron-stellarator. Unusually, the frequencies of the successive ICE spectral peaks are not close to integer multiples of the local cyclotron frequency of an energetic ion population in the likely emitting region.…
Preprint2020
UKAEA-CCFE-PR(20)101
M. Sasaki T. Kobayashi R. O. Dendy Y. Kawachi H. Arakawa S. Inagaki
A method to quantify the energy transfer among turbulent structures using singular value decomposition (SVD) is presented. We apply the method to numerical turbulence data obtained from a global plasma simulation using the Hasegawa-Wakatani fluid model, in which the Kelvin-Helmholtz instability plays a dominant role. Using the SVD method, …
Preprint Purchase2019
UKAEA-CCFE-PR(19)32
M Sasaki Y Kawachi R O Dendy H Arakawa N Kasuya F Kin K Yamasaki S Inagaki
The novel technique of dynamical mode decomposition (DMD) is applied to the outputs of a numerical simulation of Kelvin-Helmholtz turbulence in a cylindical plasma, so as to capture and quantify the time evolution of the dominant nonlinear structures. These structures comprise rotationally symmetric deformations together with spiral patterns, which…
Preprint Published2019
UKAEA-CCFE-PR(19)24
B C G Reman R O Dendy T Akiyama S C Chapman J W S Cook H Igami S Inagaki K Saito G S Yun
Ion cyclotron emission (ICE) is detected from all large toroidal magnetically con ned fusion (MCF) plasmas. It is a form of spontaneous suprathermal radiation, whose spectral peak frequencies correspond to sequential cyclotron harmonics of energetic ion species, evaluated at the emission location. We fi rst present an account of the worldwide exper…
Preprint Published2015
CCFE-PR(15)64
H. Zhu R.O. Dendy S.C. Chapman S. Inagaki
It is known that rapid edge cooling of magnetically confined plasmas can trigger heat pulses that propagate rapidly inward. These can result in large excursion, either positive or negative, in the electron temperature at the core. A set of particularly detailed measurements was obtained in Large Helical Device(LHD) plasmas [S. Inagaki et al, Plasma…
Preprint Published2013
R O Dendy S C Chapman S Inagaki
In some magnetically confined plasmas, an applied pulse of rapid edge cooling can trigger either a positive or negative excursion in the core electron temperature from its steady state value. We present a new model which captures the time evolution of the transient, non-diffusive local dynamics in the core plasma. We show quantitative agreement bet…
Published2009