Science, Simply Explained
Solar Activity and Space Radiation, Simply Explained
What are solar flares and why should YOU know about them?
In general, solar activity consists of coronal mass ejections (known as CMEs), solar flares, solar wind, and solar energetic particles. A solar flare is associated with the release of magnetic energy from the sun. The flares can vary in duration from minutes to hours. In fact, these very flares are, essentially, large explosions in our solar system. We can usually identify solar flares from the amount of light they emit. However, scientists utilize x-rays and optical light in order to monitor these events. Solar flares are only a problem when they occur on the side of our sun that faces earth. The photons are emitted directly from the site of the flare, which means if you can see the solar flare, it can affect you.
CME’s are another form of solar activity. Magnetic fields structure the corona (outer solar atmosphere). When the magnetic fields are closed, typically above sunspot groups, the trapped atmosphere can release gas bubbles and magnetic fields. These are the Coronal Mass Ejections. Large CMEs can hold up to a billion tons of matter accelerating millions of miles per hour. The solar material can impact anything such as planets or even spacecraft in its path. A CME will hit Earth only if the cloud is aligned in our direction. CME’s may be grouped with flares but is possible for the two to happen separately.
Solar wind can stem from areas known as coronal holes on the sun. These can be found anywhere on the surface, but they may impact the earth if they emanate from the equator. Solar energetic particles are charged particles that have a lot of energy. It’s believed that these particles are sent by shocks from the front of the CMEs and flares. Fast-moving solar particles may form when the CME cloud moves through the solar wind. Because these particles are charged, they move according to the magnetic field lines that lie between Earth and the sun. As a result, only the magnetic field lines that lead to Earth will have an impact on us.
Geomagnetic storms are another facet when it comes to space weather and our planet. The magnetic field creates this magnetosphere around Earth. The magnetic field serves as a shield, protecting us from the barrage of particles emitted by the sun. When particles or CMEs reach Earth, the field reacts accordingly. If the incoming magnetic field is directed northward, it works in tandem with the Earth’s opposing field (opposites attract!). Our magnetic field is peeled open by this interaction and exposed to the solar wind particles. They follow the field lines to hit the atmosphere over the poles. The storm decreases the Earth’s magnetic field strength for about six to 12 hours. Fortunately, the field recovers over a few days.
How is this event relevant to society? Well, much of our technology is susceptible to space weather. The electrical currents that flow along the surface during events can disrupt electrical power grids and even corrode oil and gas pipelines. The changes in the ionosphere during this period also afflicts GPS and high-frequency radio communications. Aircraft exposed to the particles and solar events will experience operational anomalies (temporary), blind optical imaging, among other problems.
Apparently, traveling throughout the solar system poses a risk for robots and humans alike due to solar activity. Research shows astronauts that are exposed to solar particle radiation can arrive at their limits just hours after onset. In 1989, the Hydro-Québec power network collapsed because of GICs (geomagnetically induced currents). The general blackout lasted more than nine hours affecting over 6 million people. The storm responsible was caused by a CME ejection just a few days prior.
There are ways to adjust to these space-based events. If the high-frequency radio is unavailable due to the increase of ionized gas, aircraft must be sent to fly at other latitudes where satellite comms are available. Significant solar energetic particles events have not occurred during manned space missions. However, one did happen in August 1972, between the Apollo 16 and Apollo 17 missions. The event would’ve been life-threatening for the astronauts on these missions.
Scientists also use ground and space-based sensors/imaging systems to see the activity at these depths in the solar atmosphere. Shock waves from CME-solar wind collisions are found by using receivers and transmitters. Magnetometers record the changes in the magnetic field, and cameras such as UV cameras give us a look at the auroral patterns above Earth. There are several ways we can deal with solar events, even if the actual events are out of our control.
Space Radiation
The earth is encapsulated by a magnetic field. The magnetic field protects us from space radiation by shielding the planet from particles released by solar flares and cosmic rays. The field also keeps charged particles and restrict them from leaving. These charged particles accumulate to make donut-shaped clouds around Earth, and these are called “van Allen Radiation Belts” These belts were found by Dr. James van Allen by using the satellites NASA launched in 1958. The belt’s radiation consists primarily of protons and electrons. Radiation belts exist around Jupiter, granted they are significantly larger than earth’s. Another place to find these belts would be the store around stars known as pulsars.
Space radiation can also affect electronics. There are three types of effects to consider when discussing radiation effects inside satellites. Let’s break it down below.
1. Total ionizing dose
The effects in electronics are due to damage that amasses over a lengthy period of time in the insulating region of a device. The device’s properties are altered causing its stability and performance to degrade. Eventually, the device is rendered useless.
2. Displacement damage
This type of damage is also cumulative, however, it afflicts the device’s semiconductor material. As a result, the device could begin to deteriorate and then fail to operate if subjected to enough radiation.
3. Single event effects
Caused when a single particle travels through a sensitive area in the device. The single even effect could ultimately end up being either destructive or inconsequential to the device, sometimes the effect being so small that it’s hardly noticeable. At worst, it could shut down one of the satellite’s systems.
Space radiation could also cause an increase of electrical charge within an insulating material until it gets to the point where a discharge could incur serious damage. Radiation could pry into the satellite’s circuitry and consequently disable some of its functions.
Although space radiation may be troublesome for satellites miles away from the ground, they can disrupt communication systems, GPS navigation, and even air travel by the Earth’s poles. This is due to the fact that they are less protected by the magnetic field there relative to regions closer to the equator. Large coronal mass ejections from the sun can adversely affect power grids as well. The particle radiation creates disturbances in the planet’s magnetic field, creating a “magnetic storm” of sorts. Such storm could induce power surges and possibly even a blackout. Quebec experienced a blackout because of a power surge in March 1989, which goes to show just how significant these magnetic storms could be.
