Skip to main content

Plasma filament eruptions detected on the Sun, Earth-directed CME possible

Plasma filament eruptions detected on the Sun, Earth-directed CME possible

Two plasma filament eruptions were detected on the Sun on July 5, 2018, and it seems at least one weak Earth-directed Coronal Mass Ejection (CME) was produced; ETA July 9 or 10. In addition, a relatively strong farside eruption took place on July 5 and its CME (not Earth-directed) is visible in SOHO/LASCO imagery.
While solar activity remains at very low levels and there are no sunspots on the visible disk, our sun produced two plasma filament eruptions on its Earth-side and one farside eruption over the past 48 hours.
At around 23:25 UTC on July 4, a somewhat impulsive area of coronal dimming was seen in SDO/AIA 193 imagery in the southwest quadrant of the Sun, SWPC said 00:30 UTC on July 6. This activity was likely to have been the source region for a CME which was seen in STEREO-A coronagraph imagery around 13:09 UTC on July 5. SWPC added that they are still awaiting additional imagery from SOHO/LASCO in order to determine if there is an Earth-directed component.
Another filament eruption occurred near N12E11 at approximately 01:00 UTC on July 5. However, after reviewing available coronagraph imagery from SOHO/LASCO, SWPC determined that most of the eruptive material appears to have been re-absorbed into the Sun and a CME was not produced.

While we await further official analysis, take a look at AIA videos above and analysis by Dr. Tamitha Skov and CME prediction model below.
"Our Sun wakes up launching 2 Earth-directed solar storms today," Dr. Tamitha Skov said in a tweet at 01:31 UTC, July 6.
"Its a 1,2-punch! NASA model predicts impact late July 9 or early July 10. Storms are weak so effects may be moderate, but Aurora could reach mid-latitudes over several days. Expect ham radio and GPS issues as well," she said.
Image courtesy Dr. Tamitha Skov. Open image in a new tab to see the full version.
Another CME is visible in SOHO/LASCO C3 imagery starting at 12:24 UTC on July 5, this time off the northwest limb. However, this was farside eruption and its CME is not expected to affect Earth.
Image courtesy ESA/NASA SOHO/LASCO C3
Meanwhile, the solar wind environment became enhanced early July 5 after several days of near-background conditions. Solar wind speeds increased from 325 to 450 km/s and total field from less than 5 nT to 12 nT before settling near 5 nT. The phi angle varied between positive and negative solar sectors, suggesting a close proximity to the Heliospheric Current Sheet (HCS).
As a result, the geomagnetic field became active with one period of G1 - Minor geomagnetic storming observed between 18:00 and 21:00 UTC. K-index of 5 (G1 - Minor geomagnetic storm) threshold was reached at 19:36 UTC.
Solar wind parameters are expected to decrease to background levels today and are likely to remain at those levels on July 7 and 8 with a chance for active levels as a result of periodic influences from the HCS and northern crown Coronal Hole High-Speed Stream (CH HSS).
Unsettled to active geomagnetic field conditions are expected on July 6, followed by quiet levels on July 7 and 8 with occasional unsettled and active periods as a result of minor enhancements in the solar wind.
Featured image: Plasma filament eruption on July 5, 2018. Credit: NASA/SDO AIA 304


Earth smacked by an asteroid 19-miles-wide thousands of years ago: 'It rocked the Northern Hemisphere'

Camp Fire Death Toll Rises to 63