Publication

Turbulence-induced Safety Factor Profile Flattening at Rational Surfaces in Tokamaks with Low Magnetic Shear

Stephan Brunner
2025

Abstract

In this paper, we investigate the effects of ion-scale turbulence-generated currents on the local safety factor profile under conditions of low magnetic shear and proximity to rational surfaces, relevant to internal transport barrier formation. Our results show that turbulent currents can generate stationary zonal magnetic potential corrugations, producing a stepped safety factor profile with extended regions of zero magnetic shear. This change significantly affects turbulence self-interaction, resulting in a substantial decrease in turbulent transport, indicating a potential triggering mechanism for transport barrier formation.

Official source

https://infoscience.epfl.ch/entities/publication/e2a98da3-4d1e-470a-823a-6920532f52e6

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

Stephan Brunner
2025

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/e2a98da3-4d1e-470a-823a-6920532f52e6

About this result

Related concepts (30)

Magnetic reconnection

Magnetic reconnection is a physical process occurring in electrically conducting plasmas, in which the magnetic topology is rearranged and magnetic energy is converted to kinetic energy, thermal energy, and particle acceleration. Magnetic reconnection involves plasma flows at a substantial fraction of the Alfvén wave speed, which is the fundamental speed for mechanical information flow in a magnetized plasma. The concept of magnetic reconnection was developed in parallel by researchers working in solar physics and in the interaction between the solar wind and magnetized planets.

Turbulence

In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between those layers. Turbulence is commonly observed in everyday phenomena such as surf, fast flowing rivers, billowing storm clouds, or smoke from a chimney, and most fluid flows occurring in nature or created in engineering applications are turbulent.

Magnetic diffusion

Magnetic diffusion refers to the motion of magnetic fields, typically in the presence of a conducting solid or fluid such as a plasma. The motion of magnetic fields is described by the magnetic diffusion equation and is due primarily to induction and diffusion of magnetic fields through the material. The magnetic diffusion equation is a partial differential equation commonly used in physics. Understanding the phenomenon is essential to magnetohydrodynamics and has important consequences in astrophysics, geophysics, and electrical engineering.

Related publications (5)

Turbulence-induced Safety Factor Profile Flattening at Rational Surfaces in Tokamaks with Low Magnetic Shear

Chat with Graph Search

Effect of reversed magnetic shear on short wavelength ion temperature gradient modes in ADITYA–U tokamak

Rapid and localized electron internal-transport-barrier formation during shear inversion in fully noninductive TCV discharges

Magnetohydrodynamics stability of compact stellarators