NASA SDO: Electromagnetic 'Twisted rope' clue to dangerous solar storms

Model of the magnetic field in the region where occurred a major flare on December 13th 2006. 

This model has been obtained using magnetic field data obtained at the surface of the Sun by the satellite HINODE and the high resolution model MESHMHD few hours before the eruption. 

It shows that a magnetic rope (grey) is maintained in equilibrium by overlaying arcades (orange). 

Credit: Tahar Amari /Centre de physique théorique.CNRS-Ecole Polytechnique.FRANCE.

A "twisted rope" of magnetically-charged energy precedes solar storms that have the potential to damage satellites and electricity grids, French scientists said on Wednesday.

A cord of magnetic flux emerges on the Sun's surface, grows and is squeezed upwards, and the following day, the star unleashes a blast of radiation, high-energy particles and magnetised plasma.

Solar outbursts are considered a rare but increasingly worrisome risk for satellites, global positioning systems (GPS) and power grids on which modern life depends.

Reporting in the journal Nature, a team led by Tahar Amari of France's National Centre for Scientific Research (CNRS) looked at a solar storm that brewed in December 2006 and happened to be observed by a Japanese scientific satellite.

"We were able to identify the source of the eruption four days before it developed," Amari said to reporters.

"The magnetic field builds up in the shape of a twisted rope. The ends of the rope are anchored in sunspots," he said, referring to notoriously magnetised features on the solar surface.

Experts say solar storms can cause widespread breakdowns, disabling everything from power and radio to GPS geo-location and water supplies which rely on electrical pumps.

View of typical solar eruption using data from the NASA Solar Dynamic Observatory space mission. 

The Earth has been shown to show the gigantic size of the phenomena 

Credit: Tahar Amari /Centre de physique théorique.CNRS-Ecole Polytechnique.FRANCE

They begin with an explosion on the Sun's surface, known as a solar flare, sending X-rays and extreme ultra-violet radiation towards Earth at light speed.

Hours later, energetic particles follow and these electrons and protons can electrify satellites and damage their electronics.

Next are coronal mass ejections (CME), billion-tonne clouds of magnetised plasma that take a day or more to cross the Sun-Earth gap.

A solar storm in 1859 caused an electrical surge on telegraph lines that prompted some offices to catch fire and operators to receive shocks. A 1989 event caused power outages for five million people in the Canadian province of Quebec.

A 2009 report by a panel of scientists assembled by NASA warned that a catastrophic solar storm could cost the United States alone up to two trillion dollars (1.6 trillion euros) in repairs in the first year, and it could take up to 10 years to fully recover.

Predicting when these events will take place, and if Earth lies in their path, has been thwart with problems.

Eruption of the magnetic rope in the dynamic model METEOSOL after its departure from equilibrium 

Credit: Tahar Amari /Centre de physique théorique.CNRS-Ecole Polytechnique.FRANCE

On July 23, 2012, Earth narrowly missed the biggest storm in 150 years, an event big enough to "knock modern civilisation back to the 18th century," yet few humans were even aware of the peril, NASA said last July.

At present, Earth gets a few hours' warning of a solar eruption thanks to the eyes of orbiting US satellites.

But, said Amari, warning time should eventually improve.

"The work will help us fine tune knowledge about impending solar eruptions," he said.

"Using real-time magnetic data and mathematical models, it will eventually be possible to predict space weather."

More information: Characterizing and predicting the magnetic environment leading to solar eruptions, Nature, dx.doi.org/10.1038/nature13815

Earth’s magnetic field: Observing the Birkeland currents

Plots of AMPERE magnetic perturbations and radial current density from the northern hemisphere for 24 February 2014 with start times from 1530 UT through 1700 UT.

When the supersonic solar wind hits the Earth’s magnetic field, a powerful electrical connection occurs with Earth’s field, generating millions of amperes of current that drive the dazzling auroras.

These so-called Birkeland currents connect the ionosphere to the magnetosphere and channel solar wind energy to Earth’s uppermost atmosphere.

Solar storms release torrential blasts of solar wind that cause much stronger currents and can overload power grids and disrupt communications and navigation.

Now for the first time, scientists are making continuous, global measurements of the Birkeland currents, opening a new window on our understanding of our home planet’s response to solar storms.

Using the Active Magnetosphere and Planetary Electrodynamics Response Experiment, based on the 66 Iridium satellites orbiting the Earth, authors of a Geophysical Research Letters study have discovered that Earth’s response to onsets in forcing from the solar wind occurs in two distinct stages.

Currents first appear near noon in the polar regions and remain steady for about half an hour.

Then the second stage begins, when strong currents appear near midnight and eventually join the initial currents near noon.

Most of the solar wind energy is deposited in the polar atmosphere by processes initiated in the second stage.

The authors note that scientists are working to understand how the delay between the first and second stages could give near-term warning of impending space weather disruptions.

Full Citation: Anderson, B. J., H. Korth, C. L. Waters, D. L. Green, V. G. Merkin, R. J. Barnes, and L. P. Dyrud(2014), "Development of large-scale Birkeland currents determined from the Active Magnetosphere and Planetary Electrodynamics Response Experiment" - Geophys. Res. Lett., 41, 3017–3025, doi:10.1002/2014GL059941.

Plasma Plume protects the Earth against solar storms

The Earth's magnetic field, or magnetosphere, stretches from the planet's core out into space, where it meets the solar wind, a stream of charged particles emitted by the sun. 

For the most part, the magnetosphere acts as a shield to protect the Earth from this high-energy solar activity.

But when this field comes into contact with the sun's magnetic field, a process called "magnetic reconnection," powerful electrical currents from the sun can stream into Earth's atmosphere, whipping up geomagnetic storms and space weather phenomena that can affect high-altitude aircraft, as well as astronauts on the International Space Station.

Now scientists at MIT and NASA have identified a process in the Earth's magnetosphere that reinforces its shielding effect, keeping incoming solar energy at bay.

By combining observations from the ground and in space, the team observed a plume of low-energy plasma particles that essentially hitches a ride along magnetic field lines, streaming from Earth's lower atmosphere up to the point, tens of thousands of kilometers above the surface, where the planet's magnetic field connects with that of the sun.

In this region, which the scientists call the "merging point," the presence of cold, dense plasma slows magnetic reconnection, blunting the sun's effects on Earth.

John Foster

"The Earth's magnetic field protects life on the surface from the full impact of these solar outbursts," says John Foster, associate director of MIT's Haystack Observatory.

"Reconnection strips away some of our magnetic shield and lets energy leak in, giving us large, violent storms."

"These plasmas get pulled into space and slow down the reconnection process, so the impact of the sun on the Earth is less violent."

Foster and his colleagues publish their results in this week's issue of Science.

Philip Erickson

The team includes Philip Erickson, principal research scientist at Haystack Observatory, as well as Brian Walsh and David Sibeck at NASA's Goddard Space Flight Center.

Mapping Earth's magnetic shield
For more than a decade, scientists at Haystack Observatory have studied plasma plume phenomena using a ground-based technique called GPS-TEC, in which scientists analyze radio signals transmitted from GPS satellites to more than 1,000 receivers on the ground.

Large space-weather events, such as geomagnetic storms, can alter the incoming radio waves—a distortion that scientists can use to determine the concentration of plasma particles in the upper atmosphere.

Using this data, they can produce two-dimensional global maps of atmospheric phenomena, such as plasma plumes.

These ground-based observations have helped shed light on key characteristics of these plumes, such as how often they occur, and what makes some plumes stronger than others but as Foster notes; "this two-dimensional mapping technique gives an estimate only of what space weather might look like in the low-altitude regions of the magnetosphere."

To get a more precise, three-dimensional picture of the entire magnetosphere would require observations directly from space.

Toward this end, Foster approached Walsh with data showing a plasma plume emanating from the Earth's surface, and extending up into the lower layers of the magnetosphere, during a moderate solar storm in January 2013.

Walsh checked the date against the orbital trajectories of three spacecraft that have been circling the Earth to study auroras in the atmosphere.

As it turns out, all three spacecraft crossed the point in the magnetosphere at which Foster had detected a plasma plume from the ground.

The team analyzed data from each spacecraft, and found that the same cold, dense plasma plume stretched all the way up to where the solar storm made contact with Earth's magnetic field.

More information: "Simultaneous Ground- and Space-Based Observations of the Plasmaspheric Plume and Reconnection" Science, 2014.

Supercomputers capture turbulence in the solar wind

Solar storms unleash bursts of radiation that can reach crew and passengers on commercial flights at certain altitudes and latitudes. 

Eventually the system could be used to log radiation exposure over longer periods of time for pilots and flight crews. 

Credit: NASA

As inhabitants of Earth, our lives are dominated by weather.

Not just in the form of rain and snow from atmospheric clouds, but also a sea of charged particles and magnetic fields generated by a star sitting 93 million miles away—our Sun.

This phenomenon is called solar wind.

When strong magnetic storms occur on the Sun, tons of highly energetic particles are released into the solar wind.

If these particles were free to hit the Earth, the radiation would cause life-threatening damage to our DNA, debilitate power grids, disrupt communications networks and damage electronic devices.

Fortunately for us, the Earth's magnetic dipole field and magnetosphere act as an invisible shield barring these particles from plummeting through the atmosphere.

However, this magnetic shield is not perfect and during particularly intense solar storms the magnetosphere can "crack," allowing charged particles to seep in and wreak havoc on the Earth's technological infrastructure—an event calledspace weather.

Homa Karimabadi

Scientists currently do not have the ability to accurately predict the severity of a space weather event or where it will have the most impact but a team of researchers led by University of California, San Diego's (UCSD's) Homa Karimabadi is hoping to change that.

"One of the challenges in developing accurate predictive forecasts is that the solar wind is turbulent, and the details of turbulence are not well understood," says Karimabadi, who heads the space plasma simulation group at UCSD.

Because turbulence in the solar wind occurs on widely different scales of physics—from planet-size to the sub-atomic—it is especially difficult to study but using supercomputers at the National Institute of Computational Sciences (NICS), Karimabadi and his colleagues managed to simulate all the scales of solar wind turbulence at once—for the first time ever.

Burlen Loring

To make sense of this massive dataset, they tapped Lawrence Berkeley National Laboratory (Berkeley Lab) Visualization Specialist Burlen Loring, who developed custom analysis tools using supercomputers at the National Energy Research Scientific Computing Center (NERSC).

Loring's work allows researchers to study turbulence in unprecedented detail, and the results may hold clues about some of the processes that lead to destructive space weather events. This work was published in Physics of Plasmas.

More information: Read the paper: hpcvis.com/PhysPlasmas_20_012303.pdf

Irish Radio observatory finds link: solar storms and radio bursts

New research by scientists at Trinity College Dublin, University College London, and the University of Hawai'i, published online in Nature Physics, has shown for the first time a direct link between solar storms, shock waves and solar radio bursts.

The Sun gives light and heat that makes life possible on Earth.

It can, however, have more sinister effects, sometimes unleashing huge eruptions of hot gas, called solar storms, which carry billions of tons of matter travelling at millions of kilometres an hour in Earth's direction.

These storms can be accompanied by solar radio bursts, which can cause damaging effects on many of the technologies that we rely on in our everyday lives.

Eoin Carley

"Radio bursts from solar storms can have adverse effects on both satellite and terrestrial communications. In fact, mobile phone networks can experience increased dropped-calls during periods of increased solar activity," said Eoin Carley, Irish Research Council PhD student at the School of Physics, Trinity College Dublin and first author on a recent paper on this topic in Nature Physics.

Despite decades of study, the link between solar storms and solar radio bursts has remained unclear.

This led Professor Peter Gallagher, a solar physicist at Trinity's School of Physics, to establish a radio observatory at Birr Castle in the midlands of Ireland to monitor solar radio bursts.

"What we have found is fascinating – a real insight into how solar radio bursts are created", said Professor Gallagher.

"Using antennas at Trinity's Rosse Observatory in Birr Castle together with images from NASA's STEREO and Solar Dynamics Observatory spacecraft, we have identified a missing link between solar storms and radio bursts."

Birr Castle Observatory

The findings, which were published online this week in Nature Physics, show that solar storms create huge shock waves that race through the solar atmosphere at millions of kilometres per hours.

As they do, they can accelerate electrons to huge energies, which then produce radio waves.

"Our results not only give an insight into the fundamental physics of explosions on the Sun, but enable us to better understand how the Sun affects the Earth and potentially its impacts on our daily lives" according to Carley.