Source and Propagation of a Streamer Blowout Coronal Mass Ejection Observed by the <i>Parker Solar Probe</i>

<p>In the first orbit of the Parker Solar Probe (PSP), in situ thermal plasma and magnetic field measurements were collected as close as 35 R<sub>Sun</sub> from the Sun, an environment that had not been previously explored. During the first orbit of PSP, the spacecraft flew through a streamer blowout coronal mass ejection (SBO-CME) on 2018 November 11 at 23:50 UT as it exited the science encounter. The SBO-CME on November 11 was directed away from the Earth and was not visible by L1 or Earth-based telescopes due to this geometric configuration. However, PSP and the STEREO-A spacecraft were able to make observations of this slow (v ≈ 380 km s<sup>-1</sup>) SBO-CME. Using the PSP data, STEREO-A images, and Wang-Sheeley-Arge model, the source region of the CME is found to be a helmet streamer formed between the northern polar coronal hole and a mid-latitude coronal hole. Using the YGUAZU-A model, the propagation of the CME is traced from the source at the Sun to PSP. This model predicts the travel time of the flux rope to the PSP spacecraft as 30 hr, which is within 0.33 hr of the actual measured arrival time. The in situ Solar Wind Electrons Alphas and Protons data were examined to determine that no shock was associated with this SBO-CME. Modeling of the SBO-CME shows that no shock was present at PSP; however, at other positions along the SBO-CME front, a shock could have formed. The geometry of the event requires in situ and remote sensing observations to characterize the SBO-CME and further understand its role in space weather.</p>
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