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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We report analysis of sub-Alfv\'enic magnetohydrodynamic (MHD) perturbationsin the low-\b{eta} radial-field solar wind using the Parker Solar Probespacecraft data from 31 October to 12 November 2018. We calculate wave vectorsusing the singular value decomposition method and separate the MHDperturbations into three types of linear eigenmodes (Alfv\'en, fast, and slowmodes) to explore the properties of the sub-Alfv\'enic perturbations and therole of compressible perturbations in solar wind heating. The MHD perturbationsthere show a high degree of Alfv\'enicity in the radial-field solar wind, withthe energy fraction of Alfv\'en modes dominating (~45%-83%) over those of fastmodes (~16%-43%) and slow modes (~1%-19%). We present a detailed analysis of arepresentative event on 10 November 2018. Observations show that fast modesdominate magnetic compressibility, whereas slow modes dominate densitycompressibility. The energy damping rate of compressible modes is comparable tothe heating rate, suggesting the collisionless damping of compressible modescould be significant for solar wind heating. These results are valuable forfurther studies of the imbalanced turbulence near the Sun and possible heatingeffects of compressible modes at MHD scales in low-\b{eta} plasma.

Analysis of Magnetohydrodynamic Perturbations in Radial-field Solar Wind from Parker Solar Probe Observations