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Recent work demonstrated that breaking the up-down symmetry of tokamak flux surfaces removes a constraint that limits intrinsic momentum transport, and hence toroidal rotation, to be small. We show, through MHD analysis, that ellipticity is…

Turbulence is a major factor limiting the achievement of better tokamak performance as it enhances the transport of particles, momentum and heat which hinders the foremost objective of tokamaks. Hence, understanding and possibly being able…

Plasma Physics · Physics 2013-02-26 Young-chul Ghim

The competition between drift wave and interchange physics in general E-cross-B drift turbulence is studied with computations in three dimensional tokamak flux tube geometry. For a given set of background scales, the parameter space can be…

Plasma Physics · Physics 2009-09-29 Bruce D. Scott

A large class of Laboratory, Space, and Astrophysical plasmas is nearly collisionless. When a localized energy or particle sink, for example, in the form of a radiative cooling spot or a black hole, is introduced into such a plasma, it can…

Plasma Physics · Physics 2023-03-08 Yanzeng Zhang , Jun Li , Xian-Zhu Tang

The steady-state confinement, beta limit, and divertor heat load are among the most concerned issues for toroidal confinement of fusion plasmas. In this work, we show that the negative triangularity tokamak has promising prospects to…

How thermal equilibrium is determined in a weakly collisional plasma is a fundamental question in plasma physics. This letter shows that the turbulence driven by the magnetic curvature and density gradient tends to equilibrate the…

Plasma Physics · Physics 2024-05-24 Ryusuke Numata

The development of a quasi-linear gyrokinetic transport model for tokamak plasmas, ultimately designed to provide physically comprehensive predictions of the time evolution of the thermodynamic relevant quantities, is a task that requires…

Plasma Physics · Physics 2012-04-17 Alessandro Casati

Analytic solutions of the magnetohydrodynamic equilibrium equations for a cylindrically symmetric magnetically confined plasma with reversed magnetic shear, s < 0, and sheared flow are constructed by prescribing the safety factor-, poloidal…

Plasma Physics · Physics 2007-05-23 G. Poulipoulis , G. N. Throumoulopoulos , H. Tasso

Turbulence in a superfluid in the zero temperature limit consists of a dynamic tangle of quantized vortex filaments. Different types of turbulence are possible depending on the level of correlations in the orientation of vortex lines. We…

Other Condensed Matter · Physics 2014-03-31 P. M. Walmsley , D. E. Zmeev , F. Pakpour , A. I. Golov

Nonlinear electromagnetic stabilization by suprathermal pressure gradients found in specific regimes is shown to be a key factor in reducing tokamak microturbulence, augmenting significantly the thermal pressure electromagnetic…

Near absolute zero, superfluid liquid helium displays quantum properties at macroscopic length scales. One property, superfluidity, means flow with zero viscosity. Another property, the existence of a complex wavefunction, constrains the…

Fluid Dynamics · Physics 2022-07-12 Carlo F. Barenghi

The zeroth law of turbulence states that, for fixed energy input into large-scale motions, the statistical steady state of a turbulent system is independent of microphysical dissipation properties. The behavior, which is fundamental to…

Space Physics · Physics 2021-06-16 Romain Meyrand , Jonathan Squire , Alexander A. Schekochihin , William Dorland

The flow shear associated with the differential toroidal rotation of tokamak plasmas breaks an underlying symmetry of the turbulent fluctuations imposed by the up-down symmetry of the magnetic equilibrium. Using experimental…

Plasma Physics · Physics 2017-03-08 M. F. J. Fox , F. van Wyk , A. R. Field , Y. -c. Ghim , F. I. Parra , A. A. Schekochihin

Sawtooth oscillations can trigger off heat and turbulence pulses that propagate into the edge plasma, and thus enhancing the edge shear flow and inducing a transition from low confinement mode to high confinement mode. The influences of…

Detailed computations of tokamak edge turbulence in three dimensional, globally consistent flux tube geometry show an inhibition of the standard scenario in which zonal ExB flows generated by the turbulence should lead to transport barrier…

Plasma Physics · Physics 2015-06-26 Bruce D. Scott

Shaping of magnetic flux surfaces is found to have a strong impact on turbulence and transport in tokamak edge plasmas. A series of axisymmetric equilibria with varying elongation and triangularity, and a divertor configuration are…

Plasma Physics · Physics 2010-05-10 Alexander Kendl , Bruce D. Scott

Spontaneous spin-up are widely observed in tokamak plasmas, which is crucially important for plasma confinement. A kinetic theory is proposed to show that a toroidal rotation of core plasma is induced by the topological transition of orbits…

Plasma Physics · Physics 2020-03-23 Shaojie Wang

The background magnetic geometry at the edge of a tokamak plasma has to be designed in order to mitigate the particle and energy looses essentially due to turbulent transport. The Divertor-Tokamak-Test (DTT) facility under construction at…

Plasma Physics · Physics 2024-08-01 F. Cianfrani , G. Montani

Based on the energy gradient method, criteria for turbulent transition are proposed for pressure driven flow and shear driven flow, respectively. For pressure driven flow, the necessary and sufficient condition for turbulent transition is…

Fluid Dynamics · Physics 2015-05-13 Hua-Shu Dou , Boo Cheong Khoo

A highly elongated plasma is desirable in order to increase plasma pressure and energy confinement to maximize fusion power output. However, there is a limit to the maximum achievable elongation which is set by vertical instabilities driven…

Plasma Physics · Physics 2017-05-24 Jungpyo Lee , Jeffrey P. Freidberg , Antoine J. Cerfon , Martin Greenwald