Friday, August 19th 2022, 11:20 am - Due to a combination of impacts from solar activity, most of Canada may have a chance to see auroras in the nights ahead.
The Sun has been having a very active week so far.
Following a series of flares and solar storms over the past four days, a geomagnetic storm watch is currently in effect for the nightof Friday, August 19.
Credit: NOAA SWPC
NOAA's Space Weather Prediction Center said they were anticipating the potential impact of numerous coronal mass ejections (CMEs) on Earth's magnetic field on Thursday and Friday. While each of these was expected to only have a small effect on their own, they explained, the cumulative impact was likely to increase geomagnetic activity.
Additionally, a fast stream of the solar wind, known as a coronal hole high-speed stream (CH HSS), is currently sweeping past Earth. The fast-moving particles in a CH HSS can spark auroras all on their own as they interact with Earth's magnetic field.
With the stream sweeping past us at a time when the magnetic field is already 'ringing' from the impacts of CMEs, there is a chance for geomagnetic storm activity to ramp up to even higher levels.
Geomagnetic storms can cause issues with spacecraft and satellites and possibly even fluctuations in power grids on the ground. However, they also spark vibrant displays of the Northern Lights in our night skies.
Will we see it?
The Northern Lights are typically limited only to Arctic regions. However, depending on the strength of the geomagnetic storm, the band of auroras can push far to the south.
Reasonably clear skies are necessary for aurora viewing. Based on the cloud forecast (shown above), the best areas to see any displays appearing tonight are across Alberta, Saskatchewan, and perhaps southwestern Ontario. On the map, auroras are now expected to be visible as far south as between the green (Kp=5) and yellow (Kp=7) lines.
WATCH: Will the clouds allow the auroras to shine where you live?
What's happened so far?
As of Friday morning, it appears that the CME impacts and coronal hole high-speed stream effects did not combine as expected. As a result, while geomagnetic activity was elevated, it only reached G1 (minor) geomagnetic storm levels overnight.
The graph on the left plots the average activity of Earth's magnetic field, in 3-hour increments. Green bars indicate low activity, yellow bars represent minor disturbances, and red bars indicate some level of geomagnetic storm. While activity peaked at G2 (moderate) levels on Wednesday night, it peaked at G1 (minor) on Thursday night. Brief periods of greater activity may have occurred during each 3-hour block. On the right, the maximum predicted aurora extent over Canada occurred around 12:30 a.m. EDT on Friday but did not reach as far south as expected. Credit: NOAA SWPC/Scott Sutherland
The strength of a geomagnetic storm depends on several factors. When we encounter a coronal hole high-speed stream, its impact depends on the conditions along its leading front (known as the co-rotating interaction region or CIR). The higher the density of particles along that front, the stronger its effects will be as it sweeps past Earth's magnetic field.
For coronal mass ejections, the cloud's density, the particles' energy, and the cloud's speed all play a role. The cloud also carries a magnetic field of its own, and the direction that the magnetic field points (north or south) is important for geomagnetic and aurora activity. If the field points north — the same direction as Earth's magnetic field — much of the cloud will be deflected around the planet and thus will have a reduced impact. On the other hand, a CME with a south-pointing magnetic field will have a much more significant effect, potentially sparking much higher geomagnetic activity.
Data from NOAA's Deep Space Climate Observatory (DSCOVR) indicates that the magnetic field direction fluctuated wildly between north and south during the early evening hours on Thursday. It then switched to primarily north-pointing through the rest of the night.
Real-time solar wind data from the DSCOVR satellite reveals the conditions in the near-Earth environment from 16Z (noon EDT) Thursday to 15Z (11 a.m. EDT) Friday. The top row shows the magnetic field direction, which fluctuated north and south until midnight Friday. It then mainly pointed north, which would diminish geomagnetic activity. Credit: NOAA SWPC/Scott Sutherland
According to NOAA SWPC: "We expect these disturbances to last through Friday and into Saturday, primarily at the minor to moderate level. This should keep the aurora active but at a higher latitude than yesterday."
Stay tuned for updates.
What's going on here?
Solar flares, coronal mass ejections, and geomagnetic storms are different parts of what we call space weather.
Solar flares are explosions of energy from the surface of the Sun. Look at a sunspot with the right camera filter, and you will see they are surrounded by bright 'coronal loops'. These loops appear this bright because they have tons and tons of magnetized solar matter swirling around them. The more chaotic and jumbled up these loops are, the more likely they are to suddenly and violently unravel and form new, simpler connections. When this happens, a significant amount of energy can be released, and this is what we call a solar flare. While most flares are weak, such as the A, B and C-class, we begin to take notice when we see M-class and especially the incredibly powerful X-class flares.
Sometimes, as a solar flare blasts out, it can also produce an eruption of matter from the Sun's surface known as a coronal mass ejection (CME) or 'solar storm'. These form into clouds of charged solar plasma that expand out into space from the location of the solar flare, passing through the normal flow of particles from the Sun that we call the 'solar wind'. With the chaotic jumble of magnetic fields that pierce through the Sun's surface, at times, persistent openings can form — "coronal holes" — which produce faster streams of the solar wind.
This artist impression shows the various aspects of space weather, including the last 400 years of the Sun's 11-year solar cycles, all in one graphic. Credit: NASA
A geomagnetic storm occurs when Earth's geomagnetic field — generated by the molten metal in the planet's core — experiences some kind of disturbance.
This usually happens due to changes in the solar wind or a coronal hole high-speed stream sweeping past us. Occasionally (and more frequently towards the 'peak' of a solar cycle), we see these disturbances due to an encounter with a coronal mass ejection.
The disruption causes Earth's magnetic field to fluctuate, and some of the solar particles passing by us become caught in the field and are drawn down into Earth's atmosphere.
Since these particles carry a significant amount of energy, when they collide with atoms and molecules of oxygen and nitrogen in our atmosphere, they transfer some of that energy in the process. The atoms and molecules then dump that energy, emitting it as flashes of coloured light. These flashes are what we see during displays of the Aurora Borealis and Aurora Australis, aka the Northern and Southern Lights.
Different types and colour combinations of auroras are shown here. Reds and greens are emitted by oxygen, while blues and pinks are produced by nitrogen. Arcs and pillars (Tobias Bjørkli/PIXELS), Bands and rays (GETTY), Corona (CBC), Rays and Pillars (AuroraMax/CSA), Patches and STEVE (Team Tanner)
Aurora displays are harmless wonders to behold, occurring between 100-400 km above our heads. Still, space weather does have its dangers.
Intense solar flares bombard the planet's upper atmosphere with x-rays, resulting in prolonged radio blackouts. Astronauts on board the International Space Station take shelter in shielded spacecraft until such a flare subsides. Also, orbiting satellites and spacecraft can suffer electrical problems during geomagnetic storms. Exceptionally strong geomagnetic storms can even cause electrical blackouts on the ground.
This artist's rendition shows the extent of the 1989 Quebec Blackout, which was caused by an intense geomagnetic storm. Credit: NASA
No danger is expected from this week's space weather events. However, power grid managers could see issues with our systems on the ground as the geomagnetic storm strength ramps up.
Thumbnail image provided by Alberta aurora chasers Tree and Dar Tanner.