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 present a statistical analysis of coronal mass ejections (CMEs) imaged bythe Heliospheric Imager (HI) instruments aboard NASAs twin-spacecraft STEREOmission between April 2007 and August 2017 for STEREO-A and between April 2007and September 2014 for STEREO-B. The analysis exploits a catalogue that wasgenerated within the FP7 HELCATS project. Here, we focus on the observationalcharacteristics of CMEs imaged in the heliosphere by the inner (HI-1) cameras.More specifically, in this paper we present distributions of the basicobservational parameters - namely occurrence frequency, central position angle(PA) and PA span - derived from nearly 2000 detections of CMEs in theheliosphere by HI-1 on STEREO-A or STEREO-B from the minimum between SolarCycles 23 and 24 to the maximum of Cycle 24; STEREO-A analysis includes afurther 158 CME detections from the descending phase of Cycle 24, by which timecommunication with STEREO-B had been lost. We compare heliospheric CMEcharacteristics with properties of CMEs observed at coronal altitudes, and withsunspot number. As expected, heliospheric CME rates correlate with sunspotnumber, and are not inconsistent with coronal rates once instrumentalfactors/differences in cataloguing philosophy are considered. As well as beingmore abundant, heliospheric CMEs, like their coronal counterparts, tend to bewider during solar maximum. Our results confirm previous coronagraph analysessuggesting that CME launch sites don't simply migrate to higher latitudes withincreasing solar activity. At solar minimum, CMEs tend to be launched fromequatorial latitudes while, at maximum, CMEs appear to be launched over a muchwider latitude range; this has implications for understanding the CME/solarsource association. Our analysis provides some supporting evidence for thesystematic dragging of CMEs to lower latitude as they propagate outwards.

solar physics

CMEs in the Heliosphere: I. A Statistical Analysis of the Observational  Properties of CMEs Detected in the Heliosphere from 2007 to 2017 by  STEREO/HI-1