UKAEA Journals

Showing 1 - 10 of 14 Journals Results
2021
UKAEA-CCFE-PR(21)73

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 regi…

Preprint
2021
UKAEA-CCFE-PR(21)09

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…

Preprint Purchase
The published version of this paper is currently under embargo and will be available on 05/10/2022
2019
UKAEA-CCFE-PR(19)24

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…

Preprint Published
2016
CCFE-PR(16)41

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…

Preprint Published
2016
CCFE-PR(16)42

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 …

Preprint Published
2015
CCFE-PR(15)67

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…

Preprint
2015
CCFE-PR(15)113

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…

Preprint Published
2014

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…

Published
2011

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…

Published
2011

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 …

Published