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

The SWICS instrument aboard the ACE satellite has detected frequent intervalsin the slow solar wind and interplanetary coronal mass ejections (ICMEs) inwhich C6+ and other fully stripped ions are strongly depleted, though theionization states of elements such as Si and Fe indicate that those ions shouldbe present. It has been suggested that these outlier or dropout events can beexplained by the resonant cyclotron heating process, because these ions allhave the same cyclotron frequency as He2+. We investigate the region in thecorona where these outlier events form. It must be above the ionizationfreeze-in height and the transition to collisionless plasma conditions, but lowenough that the wind still feels the effects of solar gravity. We suggest thatthe dropout events correspond to relatively dense blobs of gas in which theheating is reduced because local variations in the Alfven speed change thereflection of Alfven waves and the turbulent cascade. As a result, the wavepower at the cyclotron frequency of the fully stripped ions is absorbed by He2+and may not be able to heat the other fully-stripped ions enough to overcomesolar gravity. If this picture is borne out, it may help to discriminatebetween resonant cyclotron heating and stochastic heating models of the solarwind.

Dropouts of Fully Stripped Ions in the Solar Wind: A Diagnostic for Wave Heating versus Reconnection