For the first time ever, NASA’s Van Allen Probes caught the before and after effects of a solar shockwave as it was happening. The event, which occurred on October 8, 2013, was triggered by an explosion that erupted on the sun’s surface, sending a shockwave of solar wind careening through space. After passing the moon, the shockwave hurtled toward Earth before running head-on into the magnetic field surrounding our planet. This impact then set off a magnetized sound pulse, which reverberated around Earth.
Though the shockwave occurred two years ago, the twin spacecraft’s data was only recently analyzed by MIT’s Haystack Observatory and the University Of Colorado, among others.
“Interplanetary shocks, traveling toward Earth from the Sun, have been observed and studied before,” John Foster, associate director of the Haystack Observatory, told Fox News. “What is of major interest in the event reported are the direct observations of the effects of the shock on Earth’s Van Allen radiation belts with sufficient detail to reveal the processes taking place. Although the main strength of the solar shock is deflected by the magnetic shield that surrounds our planet, a brief pulse of energy penetrates closer to Earth where it accelerates radiation belt electrons to ultra-relativistic energies in less than a minute.”
These radiation belt electrons are no joke. Dubbed “killer” electrons, these ultra-relativistic lightweight particles are capable of going right through a satellite. According to NASA, killer electrons cause a lot of irreparable spacecraft damage, so understanding them is a top priority. They fly around at light speed and can easily break through thick shielding before burrowing into the insulation surrounding sensitive satellite equipment. The electricity from the accumulating electrons then builds up, causing a strong internal electrical discharge. One could equate it to a bolt of lighting striking your satellite dish, potentially causing a major hiccup right in the middle of “Shark Week.”
“NASA’s Van Allen Probes twin-satellite mission was conceived and launched to provide the comprehensive observations needed to identify and understand the processes responsible energizing these high-energy particles that circle Earth,” Foster added. “The processes observed during this shock event indicate that Earth’s magnetosphere can act as a highly efficient particle accelerator capable of creating the highest (ultra-relativistic) energies in regions close to Earth in a matter of seconds.”
By better understanding these havoc-wreaking particles, NASA should be able to construct killer electron-resistant spacecrafts.
The probes maintain the same orbit within the Van Allen radiation belts, with one moving forth and the other following about an hour behind as they circle the Earth. On October 8, 2013, the lead probe was in the right place at the right time to record the events that occurred before the shockwave blast. The following probe was then able to document what happened afterwards.
“The constant activity on the surface of the Sun is punctuated by violent outbursts powered the Sun’s strong magnetic field. Solar flares emit bursts of X-rays that travel outward at the speed of light,” Foster said. “Coronal mass ejections (CMEs) are giant eruptions of hot gasses from the Sun’s outer atmosphere. As this blast wave of solar material (plasma) streams towards the planets at 1000 km/sec, it sweeps up the magnetic field in its path, creating a magnetized shockwave of the type that struck Earth’s magnetic field on October 8, 2013.”
After striking the magnetic field, the shockwave then bounced away, creating a magnetosonic pulse which flew in the opposite direction. In only a few minutes, this magnetized sound wave then propagated to the other side of the planet. As it traveled, the magnetosonic pulse collected lower-energy particles that grew in energy to 3 to 4 million electronvolts. The number of killer electrons also grew, multiplying to ten times the amount that had existed prior to the shockwave’s journey.
Foster added that while this shockwave was relatively small, “the sun is capable of explosively launching much bigger shocks.”
So what, if any, effect would a more powerful shock have on Earth?
“For shocks traveling toward our planet, Earth’s magnetic field would take the direct hit such that most of the resulting disturbance would be confined to Earth’s outer magnetic field – our magnetosphere – with the ‘noticeable’ effects being those associated with a large geomagnetic storm – bright aurora, communications disturbances, scattered electrical power outages,” Foster said.”
“At Earth’s surface, we would not expect to feel the shock itself,” he added.
Researchers are hoping this new data will lead to a better understanding of radiation-belt physics. More information can be found on MIT’s News site here.