In-Situ Multi-Spacecraft and Remote Imaging Observations of the First CME Detected by Solar Orbiter

Abstract:

On April 19th 2020 a CME was detected by Solar Orbiter at a heliocentric distance of about 0.8 AU. The configuration of Solar Orbiter and STEREO-A has provided an exceptionally clean link between remote imaging and in-situ observations of the CME. The source of the CME, launched on 15th April, was an almost entirely isolated streamer blowout observed in the COR-2 images at STEREO-A. As the CME propagated away from the Sun, it was pushed from behind by a small high speed stream causing an increase in density at the back of the CME leading to it being very well observed in STEREO-A HI images. The images are useful in determining the global shape of the CME, which shows a clear flattening of the cross-section during its propagation. We present the results of fitting a flux rope model which incorporates a structured solar wind, replicating the distortion of the CME cross-section well.

The CME was also observed in-situ on April 20th by the Wind spacecraft, with a longitudinal separation of less than 5° between Solar Orbiter and the Earth. We use the in-situ observations of the magnetic field at Solar Orbiter with those at Wind to analyse the large-scale properties of the CME and compare results to those predicted using remote observations, providing a global picture of the CME as it propagated from the Sun to 1 AU.