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 High Altitude Water Cherenkov (HAWC) array is sensitive to high energyCosmic Rays (CR) in the $\sim 10$ to $\sim 200$ TeV energy range, making itpossible to construct maps of the so called "Sun Shadow" ($SS$), i. e. of thedeficit of CR coming from the direction of the Sun. In this work, we presentthe variation of the Relative Intensity of the deficit ($SS_{RI}$) for threeyears of HAWC observations form 2016 to 2018 in which we found a cleardecreasing trend of the ($SS_{RI}$) over the studied period, corresponding tothe declining phase of the solar cycle 24. By comparing the $SS_{RI}$ with thephotospheric magnetic field evolution, we show that there is a linearrelationship between the $SS_{RI}$ and the median photospheric magnetic fieldof the Active Region belt (-40$^\circ \le$ lat $\le$ 40$^\circ$) and a inverselinear relationship with the polar photospheric magnetic field (lat $\ge \pm$60$^\circ$). The former relationship is due to the magnetic field causing adeviation of the CR, whereas the latter reflects the change of the heliosphericfield topology from multipolar to dipolar configurations. These relationshipsare valid only when the median magnetic field is lower than 8 G, during thedeclining and minimum phases of the solar cycle 24. Finally, we show thatrelativistic charged particles, in the 10 to 200 TeV energy range, aredeflected a few degrees.

Galactic Cosmic Ray Sun Shadow during the declining phase of cycle 24 observed by HAWC