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

We carry out two-dimensional magnetohydrodynamic (MHD) simulations of anensemble of Alfv\'enic fluctuations propagating in a structured, expandingsolar wind including the presence of fast and slow solar wind streams. Using anappropriate expanding box model, the simulations incorporate the effects offast-slow stream shear and compression and rarefaction self-consistently. Weinvestigate the radial and longitudinal evolution of the cross-helicity, thetotal and residual energies and the power spectra of outward and inwardAlfv\'enic fluctuations. The stream interaction is found to strongly affect theradial evolution of Alfv\'enic turbulence. The total energy in the Alfv\'enwaves is depleted within the velocity shear regions, accompanied by thedecrease of the normalized cross-helicity. The presence of stream-compressionfacilitates this process. Residual energy fluctuates around zero due to thecorrelation and de-correlation between the inward/outward waves but no netgrowth or decrease of the residual energy is observed. The radial power spectraof the inward/outward Alfv\'en waves show significant longitudinal variations.Kolmogorov-like spectra are developed only inside the fast and slow streams andwhen both the compression and shear are present. On the other hand, the spectraalong the longitudinal direction show clear Kolmogorov-like inertial ranges inall cases.

Propagation of Alfv\'en waves in the expanding solar wind with the fast-slow stream interaction