K.J.H. Phillips J.A. Rainnie L. K. Harra J. Dubau F.P. Keenan N.J. Peacock
The inclusion of collisional rates for He-like Fe and Ca ions is discussed with reference to the analysis of solar flare Fe XXV and Ca XIX line emission, particularly from the Yohkoh Bragg Crystal Spectrometer (BCS). The new data are a slight improvement on calculations presently used in the BCS analysis software in that the discrepancy in the Fe X…
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. L. Dudarev A. A. Semenov C. H. Woo
We investigate the dynamics of nucleation and the growth of voids in an irradiated material in the presence of a spatially heterogeneous dislocation microstructure. We find that, due to the sensitivity of the void nucleation rate to the local vacancy supersaturation, voids nucleate and grow almost exclusively in the regions where the density of dis…
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…
PublishedR. G. L. Vann R. O. Dendy G. Rowlands T. D. Arber N. D’Ambrumenil
The Berk–Breizman augmentation of the Vlasov–Maxwell system is widely used to model self-consistent resonant excitation and damping of wave fields by evolving energetic particle populations in magnetic fusion plasmas. The key model parameters are the particle annihilation rate, which drives bump-on-tail structure, and the linear wave damping ra…
PublishedD.B. King V.M. Nakariakov E.E. Deluca L. Golub K.G. McClements
Quasi-periodic EUV disturbances simultaneously observed in 171 Å and 195 Å TRACE bandpasses propagating outwardly in a fan-like magnetic structure of a coronal active region are analysed. Time series of disturbances observed in the different bandpasses have a relatively high correlation coefficient (up to about 0.7). The correlation has a tendenc…
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…
PublishedT. Onjun A. H. Kritz G. Bateman V. Parail
Studies of type 1 ELMy H-mode pedestals are carried out using 0 D and 1.5 D approaches. In the 0 D study, predicted pedestal temperatures are compared with 533 data points. The pedestal temperature models, with pedestal width based on magnetic and flow shear stabilization and neutral penetration, yield an RMSE of 32% and 53.4%, respectively, when c…
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