M. J. Walsh P. G. Carolan A. C. Darke M. R. Dunstan M. J. Forrest R. B. Huxford R. O’Gorman K. Pechstedt S. L. Prunty R. Scannell
Both ruby laser ( 300 points ) and NdYAG laser ( 19 points ) Thomson scattering systems are used on MAST. Fast nonlinear optical switching shunts laser beams from the four 50 Hz NdYAG lasers to obtain coaxial plasma illumination. The technique allows for future expandability to many laser systems. The ruby laser system is used in parallel. A broadb…
PublishedPatrick Blanchard Elena De La Luna Chris Gowers JET-EFDA Contributors
On the Joint European Torus ( JET ) , a key source of calibrated electron temperature T e profiles is from the measurements of the full electron cyclotron emission ( ECE ) spectrum made by a Fourier transform spectrometer ( FTS ) . It is absolutely calibrated by using a calibration source inside the vacuum vessel. High spatial and temporal resoluti…
PublishedA. Patel P. G. Carolan N. J. Conway R. J. Akers
A bremsstrahlung diagnostic has been deployed on the Mega Ampere Spherical Tokamak ( MAST ) , with matrix viewing of the full plasma cross section in a narrow region of the continuum free of spectral lines. An uncooled CCD detector is used to provide 100 Hz 128 3 128 matrix viewing of the plasma emissivity which is spectrally selected using an inte…
PublishedA. Kirk H. R.Wilson G. F. Counsell R. Akers E. Arends S. C. Cowley J. Dowling B. Lloyd M. Price M.Walsh Mast Team
This Letter provides information on the spatial and temporal structure of periodic eruptions observed in magnetically confined laboratory fusion plasmas, called edge-localized modes (ELMs), and highlights similarities with solar eruptions. Taken together, the observations presented in this Letter provide strong evidence for ELMs being associated wi…
PublishedL.-G. Eriksson P. Helander F. Andersson D. Anderson M. Lisak
Self-consistent modeling of the evolution of the plasma current during disruptions in large tokamaks is presented, taking into account both the generation of runaway electrons and their backreaction on the electric field. It is found that the current profile changes dramatically, so that the postdisruption current carried by runaway electrons is mu…
PublishedH. R.Wilson S. C. Cowley
Flux tubes confined in tokamaks are observed to erupt explosively in some plasma disruptions and edge localized modes. Similar eruptions occur in astrophysical plasmas, for example, in solar flares and magnetospheric substorms. A single unifying nonlinear evolution equation describing such behavior in both astrophysical and tokamak plasmas is deriv…
PublishedS. Shiraiwa S. Ide S. Itoh O. Mitarai O. Naito T. Ozeki Y. Sakamoto T. Suzuki Y. Takase S. Tanaka T. Taniguchi M. Aramasu T. Fujita T. Fukuda X. Gao M. Gryaznevich K. Hanada E. Jotaki Y. Kamada T. Maekawa Y. Miura K. Nakamura T. Nish
A new operational scenario of advanced tokamak formation was demonstrated in the JT-60U tokamak. This was accomplished by electron cyclotron and lower hybrid waves, neutral beam injection, and the loop voltage supplied by the vertical field and shaping coils. The Ohmic heating (OH) solenoid was not used but a small inboard coil (part of the shaping…
PublishedC. Courtois R.A.D. Grundy A.D. Ash D.M. Chambers N.C. Woolsey R.O. Dendy K.G. McClements
Results from an experimental study of the collisionless interaction of two laser-produced plasmas in a magnetic field with applications to supernova remnant shock physics are presented. The dynamics of the two plasmas and their interaction are studied with and without magnetic field through spatially and temporally resolved measurements of the elec…
PublishedA.J. Webster H.R. Wilson A.M.M. Scaife
A tokamak’s economic performance is strongly affected by the plasma pressure that it may sustain, which in turn is limited by the maximum pressure gradients that may be supported. Ballooning modes are typically driven unstable by increasing the pressure gradient, and because they can radially extend across many rational surfaces, they can serious…
PublishedC.G. Gimblett R.J. Hastie
An investigation is presented of the effect of an error field on the growth of a resistive wall mode (RWM). This issue is of importance to many toroidal confinement devices, but particularly to the proposed International Thermonuclear Experimental Reactor (ITER) [ITER Physics Basis, Nucl. Fusion 39 , 2175 (1999)], where if advanced tokamak performa…
Published