UKAEA Papers

"A bundle divertor for a fusion reactor"

• AD Sanderson
• PE Stott

"Interpreting observations of ion cyclotron emission from Large Helical Device plasmas with beam-injected ion populations"

• 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 conned 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 first present an account of the worldwide exper…

"Quantifying Fusion Born Ion Populations in Magnetically Confined Plasmas"

• L. Carbajal
• R. O. Dendy
• S. C. Chapman
• J.W. S. Cook

Ion cyclotron emission (ICE) offers a unique promise as a diagnostic of the fusion born alpha-particle population in magnetically confined plasmas. Pioneering observations from JET and TFTR found that ICE intensity PICE scales approximately linearly with the measured neutron flux from fusion reactions, and with the inferred concentration, na=ni, of…

"Stimulated emission of fast Alfven waves within magnetically confined fusion plasmas"

• J. W. S. Cook
• R.O. Dendy
• S.C. Chapman

A fast Alfven wave with a finite amplitude is shown to grow by a stimulated emission process that we propose for exploitation in toroidal magnetically confined fusion plasmas. Stimulated emission occurs while the wave propagates inward through the outer midplane plasma, where a population inversion of the energy distribution of fusion-born ions is …

"Hybrid simulations of preferential ion heating due to intermittent magnetic fields in the solar wind"

• L. Carbajal
• S. C. Chapman
• R. O. Dendy
• N. W. Watkins
• J. W. S. Cook

Preferential ion heating in the solar wind, observed as the occurrence of an ion beam which drifts along the background magnetic field with a velocity close to the local Alfven speed, is still an open problem. Several mechanisms have been identified that might work together in the solar wind to drive the observed ion heating. These mechanisms resul…

"Fast particle-driven ion cyclotron emission (ICE) in tokamak plasmas and the case for an ICE diagnostic in ITER"

• K.G. McClements
• R. D’Inca
• R.O. Dendy
• L. Carbajal
• S.C. Chapman
• J.W.S. Cook
• R.W. Harvey
• W.W. Heidbrink
• S.D. Pinches

The detection of fast particle-driven waves in the ion cyclotron frequency range (ion cyclotron emission or ICE) could provide a passive, non-invasive diagnostic of confined and escaping fast particles (fusion a-particles and beam ions) in ITER, and would be compatible with the high radiation environment of deuterium–tritium plasmas in that devic…

"Linear and nonlinear physics of the magnetoacoustic cyclotron instability of fusionborn ions in relation to ion cyclotron emission"

• L. Carbajal
• R. O. Dendy
• S. C. Chapman
• J. W. S. Cook

The magnetoacoustic cyclotron instability (MCI) probably underlies observations of ion cyclotron emission (ICE) from energetic ion populations in tokamak plasmas, including fusion-born alpha-particles in JET and TFTR [Dendy et al., Nucl. Fusion 35, 1733 (1995)]. ICE is a potential diagnostic for lost alpha-particles in ITER; furthermore, the MCI is…

"Gyrobunching and wave-particle resonance in the lower hybrid drift instability"

• J W S Cook
• R O Dendy
• S C Chapman

We report a first principles study of the coupled evolution of energetic ions, background majority ions, electrons and electromagnetic fields in magnetised plasma during the linear phase of the lower hybrid drift instability. A particle-incell code, with one spatial and three velocity space co-ordinates, is used to analyse the evolving distribution…

"Self-consistent kinetic simulations of lower hybrid drift instability resulting in electron current driven by fusion products in tokamak plasmas"

• J W S Cook
• S C Chapman
• R O Dendy

We present particle-in-cell (PIC) simulations of minority energetic protons in deuterium plasmas, which demonstrate a collective instability responsible for emission near the lower hybrid frequency and its harmonics. The simulations capture the lower hybrid drift instability in a regime relevant to tokamak fusion plasmas, and show further that the …

"Electron Current Drive by Fusion-Product-Excited Lower Hybrid Drift Instability"

• J.W.S. Cook
• S.C. Chapman

We present first principles simulations of the direct collisionless coupling of the free energy of fusionborn ions into electron current in a magnetically confined fusion plasma. These simulations demonstrate, for the first time, a key building block of some ‘‘alpha channeling’’ scenarios for tokamak experiments. Spontaneously excited obliq…