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 Plus annual

Presents the access of premium content as premium feature

Premium Content

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 annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

With the ultimate aim of using the fundamental or $f$-mode to studyhelioseismic aspects of turbulence-generated magnetic flux concentrations, weuse randomly forced hydromagnetic simulations of a piecewise isothermal layerin two dimensions with reflecting boundaries at top and bottom. We computenumerically diagnostic wavenumber-frequency diagrams of the vertical velocityat the interface between the denser gas below and the less dense gas above. Foran Alfv\'en-to-sound speed ratio of about 0.1, a 5% frequency increase of the$f$-mode can be measured when $k_xH_{\rm p}=3$-$4$, where $k_x$ is thehorizontal wavenumber and $H_{\rm p}$ is the pressure scale height at thesurface. Since the solar radius is about 2000 times larger than $H_{\rm p}$,the corresponding spherical harmonic degree would be 6000-8000. For weakerfields, a $k_x$-dependent frequency decrease by the turbulent motions becomesdominant. For vertical magnetic fields, the frequency is enhanced for$k_xH_{\rm p}\approx4$, but decreased relative to its nonmagnetic value for$k_xH_{\rm p}\approx9$.

Properties of $p$- and $f$-modes in hydromagnetic turbulence