Modeling the effect of anisotropic pressure on tokamak plasmas normal modes and continuum using fluid approaches

Extending the ideal MHD stability code MISHKA, a new code, MISHKA-A, is developed to study the impact of pressure anisotropy on plasma stability. Based on full anisotropic equilibrium and geometry, the code can provide normal mode analysis with three fluid closure models: the single adiabatic model (SA), the double adiabatic model (CGL) and the incompressible model. A study on the plasma continuous spectrum shows that in low beta, large aspect ratio plasma, the main impact of anisotropy lies in the modification of the BAE gap and the sound frequency, if the q profile is conserved. The SA model preserves the BAE gap structure as ideal MHD, while in CGL the lowest frequency branch does not touch zero frequency at the resonant flux surface where $m+nq=0$, inducing a gap at very low frequency. Also, the BAE gap frequency with bi-Maxwellian distribution in both model becomes higher if $p_\perp > p_\parallel$ with a q profile dependency. As a benchmark of the code, we study the m/n=1/1 internal kink mode. Numerical calculation of the marginal stability boundary with bi-Maxwellian distribution shows a good agreement with the generalized incompressible Bussac criterion [A. B. Mikhailovskii, Sov. J. Plasma Phys 9, 190 (1983)]: the mode is stabilized(destabilized) if $p_\parallel < p_\perp (p_\parallel > p_\perp)$

Magnetohydrodynamic normal mode analysis of plasma with equilibrium pressure anisotropy

In this work, we generalise linear magnetohydrodynamic (MHD) stability theory to include equilibrium pressure anisotropy in the fluid part of the analysis. A novel 'single-adiabatic' (SA) fluid closure is presented which is complementary to the usual 'double-adiabatic' (CGL) model and has the advantage of naturally reproducing exactly the MHD spectrum in the isotropic limit. As with MHD and CGL, the SA model neglects the anisotropic perturbed pressure and thus loses non-local fast-particle stabilisation present in the kinetic approach. Another interesting aspect of this new approach is that the stabilising terms appear naturally as separate viscous corrections leaving the isotropic SA closure unchanged. After verifying the self-consistency of the SA model, we re-derive the projected linear MHD set of equations required for stability analysis of tokamaks in the MISHKA code. The cylindrical wave equation is derived analytically as done previously in the spectral theory of MHD and clear predictions are made for the modification to fast-magnetosonic and slow ion sound speeds due to equilibrium anisotropy.Comment: 19 pages. This is an author-created, un-copyedited version of an article submitted for publication in Plasma Physics and Controlled Fusion. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from i

Meat: A Novel

An English-language translation of a Russian novel that appeared in the Soviet thick journal Novyi Mir in three installments during February, March, and April of 1936

The EU and its Neighbours: Predictions for 2015. CEPS Commentary, 5 January 2015

Against a backdrop of chaos and violence in the EU’s neighbourhood, Steven Blockmans acknowledges that the troubles of 2014 will cast a long, dark shadow over 2015. In this new CEPS Commentary the author attempts to predict some of the EU foreign policy developments that are likely to mark the New Year

The Teach-in on Global Warming Solutions and Vygotsky: Fostering ecological action and environmental citizenship

The Teach-in on Global Warming Solutions is part of a larger socio-environmental movement concerned with combating climate change. Highlighting the history and elements of the teach-in as a model of learning, the article examines the teach-in movement, using a local event at the University of Calgary as an illustration. Conceptual resources from Vygotsky – the Zone of Proximal Development, and learning as social/relational transaction – are used to illuminate specific aspects of the teach-in. The article concludes by discussing the challenges and opportunities facing the global warming movement regarding public education.Le forum éducatif sur les solutions possibles au réchauffement de la planète est partie intégrante d’un vaste mouvement socio-environnemental visant à lutter contre les changements climatiques. Retraçant l’historique et les éléments du forum qui en font un modèle d’apprentissage en s’appuyant sur un événement ayant eu lieu à l’Université de Calgary, cet article fait l’examen du mouvement des forums éducatifs. Les concepts mis de l’avant par Vygotsky – tels que la zone proximale de développement et la cognition résultant de processus d’interaction socio-relationnelle – sont mis à profit pour illustrer les défis et les opportunités auxquels font face les tenants des mouvements anti-réchauffement climatique en termes d’éducation publique

Is a Concordat over Ukraine now conceivable with Mishka the bear? CEPS Commentary, 21 December 2014

With the tumultuous year of ever-changing episodes in Ukraine coming to a close – from Yanukovich reneging at Vilnius last November, to the new Maidan, to Yanukovich fleeing for his life, to Russia’s annexation of Crimea and incursions into the eastern Donbass, the election of pro-European President Poroshenko, the war with over 4,000 dead, the election of a new pro-European parliament and now the crash of the rouble – Michael Emerson sees at last a possible the end-game in sight. In this commentary, he sketches the essential elements of a Concordat to be struck between Russia, Ukraine and the West that would allow the eastern Donbass to be drawn into more normal processes of political and economic negotiation and the badly wounded Russia to gradually return to more normal international relations