NLN Aurora Brief – October 29, 2015

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Aurora Brief Number 10 of 14
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Today on the Sun:

Today AR2436 and AR2437, both rotating out of view on the western limb, produced 3 low level C-class flares. None of them will impact Earth as they are low level, did not produce CMEs and are well outside of the Earth strike zone. Other active regions 2441 and 2442 both showed signs of growth. More exciting, a new fairly large active region is rotating onto the East limb now – it will likely be numbered tomorrow. This region seems to be what was responsible in the overall increase in background x-ray activity over the last several days. Once the region is more in view, it will be easier to classify it and determine the flare risk that it presents. Here’s an image of that spot group on Magnetogram.

Magnetogram show new active region rotating into view
Magnetogram show new active region rotating into view

There was a filament eruption around midday from the south west center disk. This eruption may have an Earth-directed component but analysis will be difficult because it happened at the same time that SDO callibration was occurring.

NLN is continuing to monitor the transequitorial coronal hole as it approaches the center point of the solar disk. This is the same active region that created aurora activity on it’s previous two rotations (September 10, October 6). On the previous rotation it produced a period of G3 storming. It has not changed much in appearance, so it is expected to put on a similar show Nov 1-3.

Big coronal hole on the Solar equator may produce aurora Nov 1-3
Big coronal hole on the Solar equator may produce aurora Nov 1-3

This Day in 2003:

Active region 486 is now the largest of Solar Cycle 23 measuring in at 2300 millionths. Adding to the already active period, it launched a second Super-X flare (X10 or higher). The CME from the previous day’s X17 flare produced major storming arrived initially with a Bz south component and elevated KP levels to 9. Bz then shifted north for the next 9 hours, despite the northward shift storming continued. At the end of the 24 hour period Bz shifted sharply south and major to extreme storming resumed.

NLN Aurora Brief – October 28, 2015

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Aurora Brief Number 9 of 14
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Today on the Sun:

One new active region was numbered today, active region 2441 developed its first two spots and was given a beta classification. The biggest flare was a another slow rising long duration C3 flare from beyond the Southwest limb. It had a similar x-ray profile to yesterday’s C2 flare. Today’s flare also produced a CME but it was directed well to the west of Earth (behind) and is not expected to impact Earth’s magnetosphere.

The three day aurora forecast is now reflecting a slight rise in KP towards the end of the period. This is due to the anticipated arrival of the solar sector boundary. When the solar sector boundary crosses, the Bt component will increase. If that coincides with a negative Bz component, high latitude aurora hunters may be rewarded. This image shows the WSA-Enlil model (how to read the WSA-Enlil output) on Day 3 as the solar sector boundary approaches.

WSA Enlil model output showing Solar Sector Boundary Crossing Oct 30, 2015
WSA Enlil model output showing Solar Sector Boundary Crossing Oct 30, 2015

Notice also on the image above that the plasma density is predicted to continue to increase through the first two days of November. NLN will be covering this increase in activity over the next week.

This Day in 2003:

Active region 486 released one of the largest flares in recent memory on this day in 2003. The X17 flare generated a large fast moving CME that headed directly towards Earth. It arrived at Earth, after traveling 150 million kilometers, just 19 hours later. Almost immediately after the flare, a proton event greater than 100MeV and was measured peaking at 186pfu. This is an enormous flare, here’s an image from SDO at the time of the flare.

Huge X17 flare from Active Region 486 - Oct 28, 2003
Huge X17 flare from Active Region 486 – Oct 28, 2003

On Earth, this will start a period of Major storming that will last through Halloween and will become known as the “2003 Halloween Aurora Strom”

Happy Hunting!

NLN Aurora Brief – October 27, 2015

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Aurora Brief Number 8 of 14
Previous Brief: NLN Aurora Briefs – October 26, 2015
Next Brief: NLN Aurora Briefs – October 28, 2015

Today on the Sun:

Activity on the Sun continues to be quiet. The largest flare today was a C2.2 Flare from active region 2437. While small, this flare produced a CME that was visible on LASCO. Given the location of the flare, it seems unlikely it will have an Earth directed component, but if it does, it might impact earth on 10/29.

There are two other areas of interest on the Sun today. A new active region (AR2340) was numbered after experiencing growth just near the center line. If it continues to grow quickly, it could become a threat for flaring. Here is a view of the new Region:

Newly Numbered AR2440 in Magnetogram
Newly Numbered AR2440 in Magnetogram

In addition the long anticipated return of the coronal hole that produced aurora activity on it’s previous two rotations at the beginning of September and the beginning of October. So far, imagery indicates this coronal hole has maintained it’s structure, and Stereo A data indicated it was still generating strong solar wind 8 days ago. This is one to watch.

Coronal hole returns rotating into view on the Eastern Limb
Coronal hole returns rotating into view on the Eastern Limb

This Date in 2003:

Active Regions 484 and 486 continue to generate large flares. Together, they were responsible for 5 M-class flares. They remained about the same size and magnetic complexity. By now, this period is being talked about as one of the most active periods in solar cycle 23. Stay tuned for tomorrow when AR 486 will release one of the largest flares in recorded history

On Earth, geomagnetic activity only reached active, but over the next two days it is expected to be active with the arrival of the two 10/26 X-class flare CMEs.

Happy Hunting!