Northern Lights Now – A large coronal hole was pointed directly towards Earth on April 9th and 10th. The high speed solar wind from that exposed area is should impact Earth on April 13 and 14. Space weather forecasters are expecting two consecutive days of geomagnetic storming. That could bring several opportunities for Aurora hunters to experience the Northern and Southern Lights. Here’s an image from SDO from late on April 9 in AIA 211, a wavelength that makes it easy to see coronal holes:
SWPC is calling for two periods of active Aurora (G1 level storming). The first period is early on April 13 and the second is Early on April 14. For North American Aurora viewers this is in prime evening viewing time. Europeans viewers will have to stay up past midnight. See the NLN Aurora cast for April 13 and 14. The data behind this infographic comes from the Space Weather Prediction Center in Boulder Colorado
Note: It is not an error that both days have the same profile throughout the day. The is what the forecasting models have predicted.
Northern Lights Now – A pair of filament eruptions on April 6th likely produced CMEs that will impact Earth on April 10th and 11th, producing aurora. The first filament was about 15 degrees long along a NE-SW, with the SW terminus just to the NE of Active Region 2528. The eruption produced a wide arching and looping structure. Structures like these are often correlated with coronal mass ejections (CMEs) that have a “slinky” or coiled structure. The second, smaller filament, erupted from the southern hemisphere of the solar disk in Earth strike zone. If it did produce a CME, will likely be directed towards Earth. The two eruptions together mean there is an increased likelihood of aurora on April 10-11 as the solarstorms arrive.
In this animatedGIF (also shared on the NLN Twitter Account), watch the first filament eruption. Note the wide spread between the east and west side, and the apparent arcing between the two sides – particularly on the southern extent. The large bright area on at the southern end is active region 2528 (Beta). Towards the end of the loop, the launching Plasma material can be seen. It’s trajectory actually looks to be mosly to the North and West of the Earth-Sun line. If this storm does arrive at Earth, it will likely be a glancing blow. It is possible that additional material launched from the Eastern (right) side of the filament may not be visible in the imagery and directed towards Earth. LASCO imagary, coming available over the next 12 hours should confirm the extent and direction of the CME. Click either of the two video below for a zoomed in view.
The second eruption was much faster. The video below is taken from the last 3 hours of the same full-disk video as the one above. It is zoomed in to the central southern hemisphere of the visible disk and slowed to about half the speed. This is a fast eruption. Notice the dark area at the beginning of the clip, the eruption happens just to the north of this. It is a faint East to West wisp of plasma that lifts off temporarily hiding the dark area behind it. The eruption is in the Earth strike zone so, even though it is smaller, may have more impact on Earth than the second eruption.
Stay tuned to NLN for more updates on these two solar storms.
SWPC has now issued a G1 geomagnetic storm watch for Saturday April 2nd.
Northern Lights Now – As March draws to a close, there are a couple areas on the Solar disk with notable activity. On Sunday, a stunning solar prominence on the East limb produced a show in SDO imagery. Today, an active region that grew from alpha to beta and is now pointed straight at Earth and located between two coronal holes. Both coronal holes are in negative polarity regions and are related to coronal holes that produced negative Bz and aurora during their previous rotation. It’s possible this could happen again, but likley to a lesser degree on the current rotation.
A solar prominence happens when a large area of gas and charged particles lifts off the Sun into the corona. Prominences are visible in the 304 Angstrom images available on the SDO website. When they happen on the limb they are spectacular, as the dark sky of space acts as a backdrop to the heated gasses lift off the surface. Here’s an animated GIF of images of the prominence as it erupted on Sunday on the east limb over a 12 hour period.
It is unlikely this feature will have any impact on Earth. If it did produce a CME during the eruption, it would be well to the East of the Earth-Sun line.
A Growing Beta Active Region
Active Region 2526 has been increasing in size (from 120MH to 200MH) as it rotates toward center disk. Tonight, SWPC upgraded the magnetic classification from Alpha to Beta. The changes to the region are minor but do increase the probability of flare activity slightly. Thus far, the active region has not produced much flare activity, but keep an eye on it, this could change.
A Pair of Coronal Holes
The most promising solar feature for aurora hunters is the coronal hole that was pointed at Earth yesterday. On it’s previous pass, this coronal hole was a complex of three separate holes and lead to a prolonged period of enhanced solar wind, several periods of south-oriented Bz and a phenomenal display of Aurora. The coronal hole structure has degraded since the last rotation and is now comprised of a pair of medium sized coronal holes. Until today, when the second hole emerged to the NE of the first, this single coronal hole might have produced a short period of elevated solar wind. Now that it is a pair, Earth could experience couple days of slightly elevated soalr wind. Even better news for aurora hunters is that active region 2526 is directly between these two coronal holes, so if it does flare and produce a CME, the plasma will be accelerated by the elevated wind speed. Again, these are worth keeping an eye on the next couple days.