Solar Storms and More
Current Conditions 2017/04/03
CHANCE OF FLARES: NOAA forecasters estimate a 60% chance of M-class solar flares and a 20% chance of X-flares on April 3rd as sunspot AR2644 continues to crackle with magnetic explosions. Extreme UV radiation from such flares can cause shortwave radio blackouts and other disturbances to the normal transmission of radio signals around the globe.
THE SUN WAKES UP: Suddenly, solar flare activity is high. With little warning, sunspot AR2644 exploded on April 1st, producing an M4.4-class flare. That was the strongest solar flare of the year–for less than a day. The sunspot topped itself on April 2nd with a pair of M5-class explosions, followed by another M5-flare on April 3rd.
Flashes of extreme ultraviolet radiation, like the one shown above, have been ionizing Earth’s upper atmosphere and altering the normal propagation of radio waves around our planet. There have been at least four significant shortwave radio blackouts; blackout maps: #1, #2, #3, #4. People who might have noticed these blackouts include ham radio operators and mariners using low-frequency rigs for communication at frequencies below 10 MHz.
Update: This series of explosions hurled a number of coronal mass ejections (CMEs) into space. NOAA computer models confirm that none of them will hit Earth.
Read more at SpaceWeather.com
Current Solar Data (from NOAA)
Space Weather Conditions
USAF/NOAA 3-day Report of Solar and Geophysical Activity Report and Forecast – Updates
WSA-Enlil Solar Wind Prediction
Recently Reported Solar Events
SolarSoft’s “latest events”
The Classification of X-ray Solar Flares
or “Solar Flare Alphabet Soup”
A solar flare is an explosion on the Sun that happens when energy stored in twisted magnetic fields (usually above sunspots) is suddenly released. Flares produce a burst of radiation across the electromagnetic spectrum, from radio waves to x-rays and gamma-rays. [more information]
Scientists classify solar flares according to their x-ray brightness in the wavelength range 1 to 8 Angstroms. There are 3 categories: X-class flares are big; they are major events that can trigger planet-wide radio blackouts and long-lasting radiation storms. M-class flares are medium-sized; they can cause brief radio blackouts that affect Earth’s polar regions. Minor radiation storms sometimes follow an M-class flare. Compared to X- and M-class events, C-class flares are small with few noticeable consequences here on Earth.
This figure shows a series of solar flares detected by NOAA satellites in July 2000:
Each category for x-ray flares has nine subdivisions ranging from, e.g., C1 to C9, M1 to M9, and X1 to X9. In this figure, the three indicated flares registered (from left to right) X2, M5, and X6. The X6 flare triggered a radiation storm around Earth nicknamed the Bastille Day event.
Peak (W/m2)between 1 and 8 Angstroms
|B||I < 10-6|
|C||10-6 < = I < 10-5|
|M||10-5 < = I < 10-4|
|X||I > = 10-4|
One of the most violent sun storms in recorded history erupted 11 years ago today (July 14).
The event was called the Bastille Day Solar Storm, and it registered as an X-class flare, the highest designation possible. (One storm since then, in October 2003, was even more powerful.)
Ever wonder just how a solar storm brews? So do scientists. Here’s a rundown of what happened on July 14, 2000, one of the sun’s most violent days:
A sunspot was born. This occurred when magnetic field lines became tangled by the churning and shifting of plasma bubbles on the sun’s surface. These twisted magnetic field lines formed a sunspot — an active region that appeared darker than the surrounding area. [Infographic: Anatomy of Solar Storms & Flares]
As the magnetic field lines became more and more twisted, magnetic potential energy built up, similar to how a roller coaster car at the top of the track builds up gravitational potential energy, which is then converted to the kinetic energy of motion as the car zooms downward.
When the magnetic potential energy of the sun finally hit a certain point, it snapped, releasing that energy in the form of heat, light and the motion of particles. Plasma on the sun was heated up to 20 million or 30 million degrees Kelvin (36 million to 54 million degrees Fahrenheit). Plasma particles were accelerated along giant loops that traced magnetic field lines down through successive layers of the sun’s atmosphere.
These loops connected to form large ribbons of superheated plasma.
At the same time, some plasma particles from the sun’s atmosphere were accelerated away from the surface, out into space. Such a release of material is called a coronal mass ejection. Many of these protons and electrons made their way to Earth, where they disrupted satellites and blocked radio communications.
Though scientists understand many aspects of the storm’s process, there are still some pressing questions. One of the biggest is: What sparked the storm in the first place? [Hell Unleashed: Sun Spits Fire in Close-Up]
“The holy grail, which is not solved yet, is, what is the actual trigger mechanism that causes this buildup of energy to be released?” said Phil Chamberlin, a solar scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md.
However, the Bastille Day solar storm did go a long way toward helping scientists piece together a general theory of how eruptions on the sun occur.
“This theory is all based on observations from the Bastille Day flare,” Chamberlin told SPACE.com.
That knowledge will come in especially handy in the coming years, as the sun ramps up toward a peak in its 11-year cycle of activity. Near the end of 2013, we are likely to see storms that rival, or even surpass, the Bastille Day event.
[Byline Clara Moskowitz]
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