Kinetic-ballooning-bifurcation in tokamak pedestals across shaping and aspect-ratio
Mapping dust in the giant molecular cloud Orion A
Abstract:
The Sun is located close to the Galactic mid-plane, meaning that we observe the Galaxy through significant quantities of dust. Moreover, the vast majority of the Galaxy’s stars also lie in the disc, meaning that dust has an enormous impact on the massive astrometric, photometric and spectroscopic surveys of the Galaxy that are currently underway. To exploit the data from these surveys we require good three-dimensional maps of the Galaxy’s dust. We present a new method for making such maps in which we form the best linear unbiased predictor of the extinction at an arbitrary point based on the extinctions for a set of observed stars. This method allows us to avoid the artificial inhomogeneities (so-called ‘fingers of God’) and resolution limits that are characteristic of many published dust maps. Moreover, it requires minimal assumptions about the statistical properties of the interstellar medium. In fact, we require only a model of the first and second moments of the dust density field. The method is suitable for use with directly measured extinctions, such as those provided by the Rayleigh–Jeans colour excess method, and inferred extinctions, such as those provided by hierarchical Bayesian models like StarHorse. We test our method by mapping dust in the region of the giant molecular cloud Orion A. Our results indicate a foreground dust cloud at a distance of 350 pc, which has been identified in work by another author.Mapping dust in the giant molecular cloud Orion A
Laboratory realization of relativistic pair-plasma beams
Dataset: tests of a finite-element implementation of the nonlinear Fokker-Planck collision operator
Abstract:
Data and plots created in the course of studying a finite element implementation of the nonlinear Fokker-Planck collision operator for charged particle collisions in a low density plasma. Created with the Julia-based code "moment_kinetics" https://github.com/mabarnes/moment_kinetics.
This work was supported by the United Kingdom Atomic Energy Authority ExCALIBUR programme grant. The ExCALIBUR programme (https://excalibur.ac.uk/) is supported by the UKRI Strategic Priorities Fund. The programme is co-delivered by the Met Office and EPSRC in partnership with the Public Sector Research Establishment, the United Kingdom Atomic Energy Authority and UKRI research councils, including NERC, MRC and STFC.
This work was supported by the U.S. Department of Energy under contract number DE-AC02-09CH11466. The United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.
This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No 101052200 — EUROfusion). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them.