H. 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…
PublishedM. R. Tournianski P. G. Carolan R. J. Akers
Operating a microchannel plate ( MCP ) in saturated mode provides a simple photon and particle counting detector. However, there is a finite recovery time after individual events during which individual microchannels no longer respond, reducing the overall sensitivity. At continuous high flux levels, the corrections from measured to true flux becom…
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…
PublishedThawatchai Onjun Arnold H. Kritz Glenn Bateman Vassili Parail Howard Wilson et al.
Simulations of three Joint European Torus [P. H. Rebut et al., Nucl. Fusion 25, 1011 (1985)] type I ELMy high-confinement discharges in a power scan are carried out using the JETTO integrated modeling code [M. Erba et al., Plasma Phys. Controlled Fusion 39, 261 (1997)] with predictive core and pedestal models, which include the effect of edge local…
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…
PublishedD. R. Mccarthy C. N. Lashmore-Davies A. Thyagaraja
The generalized Charney-Hasegawa-Mima equation is unstable to a four wave modulational instability whereby a coherent, monochromatic drift wave can drive a band of modes and associated zonal flows unstable. Although initially the fastest growing modes dominate, a secondary nonlinear instability later drives the longest wavelength zonal flow and its…
PublishedS. E. Sharapov B. Alper J. Fessey N. C. Hawkes N. P. Young R. Nazikian G. J. Kramer D. N. Borba S. Hacquin E. De La Luna S. D. Pinches J. Rapp D. Testa JET-EFDA Contributors
A microwave interferometry technique is applied for the first time for detecting a discrete spectrum of Alfvén cascade (AC) eigenmodes excited with fast ions in reversed magnetic shear plasmas of the Joint European Torus. The interferometry measurements of plasma density perturbations associated with ACs show an unprecedented frequency and time re…
PublishedS. L. Dudarev A. A. Semenov C. H. Woo
We found that by assuming that the density of dislocations in an irradiated material varies as a function of the distance to grain boundaries and that mobile interstitial defect clusters perform three-dimensional diffusional motion it is possible to achieve significantly better agreement with experimental observations of profiles of heterogeneous v…
PublishedD. Hughes M. Paczuski R.O. Dendy P. Helander K.G. McClements
A model for the solar coronal magnetic field is proposed where multiple directed loops evolve in space and time. Loops injected at small scales are anchored by footpoints of opposite polarity moving randomly on a surface. Nearby footpoints of the same polarity aggregate, and loops can reconnect when they collide. This may trigger a cascade of furth…
Published