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 investigate the effects of magnetic field configurations on the ionizationrate by cosmic rays in protoplanetary disks. First, we consider cosmic-raypropagation from the interstellar medium (ISM) to the protoplanetary disks andshowed that the cosmic-ray density around the disk should be 2 times lower thanthe ISM value. Then, we compute the attenuation of cosmic rays inprotoplanetary disks. The magnetic fields in the disk are stretched to theazimuthal directions, and cosmic rays need to detour while propagating to themidplane. Our results show that the detouring effectively enhances the columndensity by about two orders of magnitudes. We employ a typical ionization rateby cosmic rays in diffuse ISM, which is considered too high to be consistentwith observations of protoplanetary disks, and find that the cosmic rays aresignificantly shielded at the midplane. In the case of the disk around IM Lup,the midplane ionization rate is very low for $r\lesssim\,100$ au, while thevalue is as large as a diffuse ISM in the outer radii. Our results areconsistent with the recent ALMA observation that indicates the radial gradientin the cosmic-ray ionization rate. The high ionization rate in the outer radiiof disks may activate the magnetorotational instability that was thought to besuppressed due to ambipolar diffusion. These results will have a stronginfluence on the dynamical and chemical evolutions of protoplanetary disks.

Cosmic-ray ionization rate in protoplanetary disks with sheared magnetic fields