Using NASA Solar Dynamic Observatory (SDO) spacecraft, professor Jie Zhang and his graduate student Xin Cheng from George Mason University discovered that phenomenon called a giant magnetic rope is the cause of solar storms. Confirming the existence of this formation is a key first step in helping to mitigate the adverse effects that solar storm eruptions can have on satellite communications on Earth.
Though the magnetic rope was believed to be the cause of these giant eruptions on the Sun, scientists had previously not been able to prove this phenomenon existed because of how quickly the rope moves.
However, through close examination of images taken by the Atmospheric Imaging Assembly (AIA) telescope on board the SDO, Zhang was able to pinpoint an area of the sun where a magnetic rope was forming. The AIA telescope suite is able to capture images of the Sun every 10 seconds, 24 hours a day. This unprecedented cadence in time helped the discovery.
A solar storm is a violent eruption from the Sun, sending billions of tons of charged material, also called plasma, into space at a speed of more than one million miles per hour. The cloud of plasma carries with it a strong magnetic field. When the magnetized cloud reaches Earth one to three days later, a huge amount of energy is deposited into the magnetosphere of the Earth.
Normally the Earth’s magnetosphere shields this harmful solar wind and protects the environment. However, a solar storm has the potential to disrupt the shielding effect and produce severe space weather, which can have harmful effects on a wide array of technological systems, including satellite operation, communication and navigation and electric power grids.
Zhang’s research will help in giving early warning about solar storms and help to minimize the damage done by space weather here on Earth.
While Dr. Wei Liu, a Stanford University Research Associate at the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL) at the company’s Advanced Technology Center (ATC) in Palo Alto, used the same Atmospheric Imaging Assembly (AIA) instrument on board NASA’s Solar Dynamics Observatory (SDO), to detect quasi-periodic waves in the low solar corona that travel at speeds as high as 2,000 kilometers per second (4.5 million miles per hour).
It is well known that the hot plasma in the solar corona oscillates and produces propagating waves when “kicked” by a flare or eruption, similar to ripples in water produced by dropping a rock into a still pond. Theories and computer models predicted the existence of slow and fast moving waves, and the former were clearly seen by solar observatories in space. However, clues for fast moving waves were seen only briefly in the past during a solar eclipse on the ground, because previous space telescopes could not take pictures rapidly enough to image these fast waves.
The waves are typically successive, arc-shaped fronts of intensity variations, similar to water ripples, which emanate near a flare kernel in the wake of a coronal mass ejection and propagate along a funnel of coronal loops. They have velocities of 1,000-2,000 kilometers per second, periods in the 30-200 seconds range, and wavelengths of 100,000-200,000 kilometers that is equivalent to stacking eight to sixteen Earths atop one another.