English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We present nonlinear resistive MHD simulations of the response of a rotatingplasma to an error field when the plasma has weakly damped linear tearing modes(TM's), stabilized by pressure gradient and favorable curvature. Favorablecurvature leads to the Glasser effect: the occurrence of real frequencies andstabilization with positive stability index $\Delta'$. A cylinder with hollowpressure is used to model the toroidal favorable curvature. Linear simulationswith rotation and an error field $\tilde{\psi}_w$ show, in agreement withanalytic results, that the peak reconnected flux occurs for a rotation ratenear the TM phase velocity. Nonlinear simulations with small $\tilde{\psi}_w$show that the real frequency and stabilization by favorable average curvatureare masked by a nonlinear effect that occurs for very thin islands: flatteningof the pressure across the island, mainly due to sound wave propagation. Thisflattening causes the disappearance of real frequencies destabilization of themode, allowing it to grow to large amplitude similar to a $\beta=0$ unstableTM. The flattening of the current for larger islands saturates the modenonlinearly. In the post-saturation phase, the interaction of the error fieldwith the destabilized spontaneous tearing mode, which rotates with the plasma,leads to oscillations in the Maxwell torque and therefore modulations in theplasma rotation. The islands also rotate with modulated phase velocity,undergoing small-amplitude oscillations due to these modulations. We alsopresent a quasilinear model with an unstable spontaneous TM and error fields,showing that the superposition of these fields results in similar oscillations.

Nonlinear error field response in the presence of plasma rotation and real frequencies due to favorable curvature