In the absence of the sun, life as we know it would not exist. In addition to providing just the right amount of heat and light for third planet inhabitants, the sun is responsible for circadian rhythms, vitamin D production and photosynthesis. However, this life-sustaining orb also carries the potential for severe destruction. Via a phenomenon known as solar wind, the sun ejects a sea of protons, electrons and ionized atoms in all directions at speeds of a million miles per hour or more. If these particles were to reach earth, the radiation would threaten human health, while the massive onslaught of charged particles would disrupt power grids, communication networks and electronic devices.
|3D global hybrid simulation of Earth’s magnetosphere. Magnetic field lines are color coded based on their origin and termination point.
Courtesy: H. Karimabadi and B. Loring. Source: NICS
Solar wind is just one kind of space weather, the term for environmental conditions in near-Earth space. Solar flares, explosive storms that occur on the surface of the sun, eject blasts of charged particles with a ferocity that’s equivalent to 10 million volcanic eruptions. Less frequent, but even more dangerous than solar wind or flares, are coronal mass ejections, or CMEs. These eruptions of plasma from inside the sun’s corona can set off space-weather events called geomagnetic storms that can wreck havoc on our planet’s inhabitants and its technology.
This non-stop space attack is held in check by a natural shield, a magnetic field known as the magnetosphere. Created by Earth’s magnetic dipole, this field extends out into space for 37,000 miles. The magnetosphere stops most charged particles from entering Earth’s atmosphere. However, it is not a perfect solution. Enough solar particles get through the magnetic net to pose a serious hazard to power grids, communication networks and living creatures.
Supercomputing to the rescue
A research group led by Homa Karimabadi of the University of California, San Diego, is investigating the effects of space weather on the magnetosphere.
“Earth’s magnetic field provides a protective cocoon, but it breaks during strong solar storms,” explains Karimabadi.
Karimabadi teamed up with visualization specialist Burlen Loring of Lawrence Berkeley National Laboratory (LBNL) to create a topological map of Earth’s magnetosphere, using the supercomputing resources at National Institute for Computational Science (NICS).
“The ‘topomap’ helps us find the location of the magnetic field lines from different sources [for example, the magnetic field of Earth versus the magnetic field of the solar wind],” said Karimabadi.
Currently, researchers can track storms, but there are no tools available for predicting storms. In this first-of-its-kind project, the researchers will leverage the map to build global kinetic simulations of the magnetosphere and space-weather effects.
The simulations are both compute- and data- intensive. A single job can require 100,000 central processing units and take 48-hours or longer to complete. It’s only since the advent of petascale supercomputers like Jaguar, Nautilus and Kraken, that such complex phenomenon as this can begin to be unraveled. And according to Karimabadi, even the fastest computers of our era still fall short. It’s ultimately an exascale problem, he says.
“Handling and analysis of massive datasets resulting from our simulations are quite challenging. Partnering with the [visualizations] group at LBNL has been critical in developing tools to analyze our data sets,” says Karimabadi.
Improved predictive capabilities are crucial in order to prepare for space-weather events. A feature article on the research notes it will lead to “a better understanding of how space weather affects our magnetosphere allows scientists to more accurately predict the impact of solar activity on our planet.”
Last July, a geometric superstorm, spawned by a CME, was narrowly avoided. If the storm had taken place only a few days sooner, there would likely have been far-reaching consequences. Such storms have the potential to take down power grids on a national or even international scale.
As previous events (in 1859 and 1989) have taught us, the danger is real. “There is an urgent need to develop accurate forecasting models,” Karimabadi asserts. “A severe space-weather effect can have dire financial and national-security consequences, and can disrupt our everyday lives on a scale that has never been experienced by humanity before.”