Ain’t Misbehavin’ – Turbulence, Solar Flares and Magnetism

In this image, the Solar Dynamics Observatory (SDO) captured an X1.2 class solar flare, peaking on May 15, 2013. Credit: NASA/SDO

What’s more fun than something that misbehaves? When it comes to solar dynamics, we know a lot, but there are many things we don’t yet understand. For example, when a particle filled solar flare lashes out from the Sun, its magnetic field lines can do some pretty unexpected things – like split apart and then rapidly reconnect. According to the flux-freezing theorem, these magnetic lines should simply “flow away in lock-step” with the particles. They should stay intact, but they don’t. It’s not just a simple rule they break… it’s a law of physics.

What can explain it? In a paper published in the May 23 issue of “Nature”, an interdisciplinary research team led by a Johns Hopkins mathematical physicist may just have found a plausible explanation. According to the group, the underlying factor is turbulence – the “same sort of violent disorder that can jostle a passenger jet when it occurs in the atmosphere” – or the one your brother leaves behind after he’s eaten baked beans. By employing a well-organized and logically constructed computer modeling technique, the researchers were able to simulate what happens when magnetic field lines meet up with turbulence in a solar flare. Armed with this information, they were then able to state their case.

“The flux-freezing theorem often explains things beautifully,” said Gregory Eyink, a Department of Applied Mathematics and Statistics professor who was lead author of the “Nature” study. “But in other instances, it fails miserably. We wanted to figure out why this failure occurs.”

Just what is the flux-freezing theorem? Maybe you’ve heard of Hannes Alfvén. He was a Swedish electrical engineer, plasma physicist and winner of the 1970 Nobel Prize in Physics for his work on magnetohydrodynamics (MHD). He’s the man responsible for explaining what we now know as Alfvén waves – a low-frequency travelling oscillation of the ions and the magnetic field in plasma. Well, some 70 years ago, he came up with the thought that magnetic lines of force sail along a locomotive fluid similar to snippets of thread flowing along a stream. It should be impossible for them to break and then join again. However, solar physicists have discovered this just isn’t the case when it comes to activity within a particularly violent solar flare. In their observations, they have determined that the magnetic field lines within these flares can stretch to the breaking point and then reconnect in a surprisingly quick amount of time – as little as 15 minutes. When this happens, it expels a copious amount of energy which, in turn, powers the flare.

“But the flux-freezing principle of modern plasma physics implies that this process in the solar corona should take a million years!” Eyink animatedly states. “A big problem in astrophysics is that no one could explain why flux-freezing works in some cases but not others.”

Of course, there has always been speculation that turbulence may have been the root source of the enigmatic behavior. Time for investigation? You bet. Eyink then joined forces – and minds – with other experts in astrophysics, mechanical engineering, data management and computer science, based at Johns Hopkins and other institutions. “By necessity, this was a highly collaborative effort,” Eyink said. “Everyone was contributing their expertise. No one person could have accomplished this.”

Gregory Eyink, professor of applied mathematics and statistics at Johns Hopkins. Photo by Nat Creamer.
Gregory Eyink, professor of applied mathematics and statistics at Johns Hopkins. Photo by Nat Creamer.
The next step was to create a computer simulation – a simulation which could duplicate the plasma state of solar flare activity and all the nuances the charged particles undergo during different conditions. “Our answer was very surprising,” stated Eyink. “Magnetic flux-freezing no longer holds true when the plasma becomes turbulent. Most physicists expected that flux-freezing would play an even larger role as the plasma became more highly conducting and more turbulent, but, as a matter of fact, it breaks down completely. In an even greater surprise, we found that the motion of the magnetic field lines becomes completely random. I do not mean ‘chaotic,’ but instead as unpredictable as quantum mechanics. Rather than flowing in an orderly, deterministic fashion, the magnetic field lines instead spread out like a roiling plume of smoke.”

Of course, other solar experts feel there may be alternative answers for this rule-breaking activity within solar flares, but as Eyink says, “I think we made a pretty compelling case that turbulence alone can account for field-line breaking.”

What is most exciting is the collaborative effort of the team members from such widely varied disciplines. It was a group effort which aided Eyink to come up with this new theory on the solar flare riddle. “We used ground-breaking new database methods, like those employed in the Sloan Digital Sky Survey, combined with high-performance computing techniques and original mathematical developments,” he said. “The work required a perfect marriage of physics, mathematics and computer science to develop a fundamentally new approach to performing research with very large datasets.”

In conclusion, Eyink noted this type of research work may very well give us a better understanding of solar flares and coronal mass ejections. As we know, this type of dangerous “space weather” can be harmful to astronauts, disrupt communications satellites, and even be responsible for the shut-down of electrical power grids on Earth. And you know what that means… no satellite TV and no power to watch it by. But, that’s O.K.

“I don’t stay out late. Don’t care to go. I’m home about eight… Just me and my radio. Ain’t misbehavin’.. Savin’ my love for you.”

Original Story Source: Johns Hopkins University News Release.

Still Concerned About 2012?

Don’t be.

Don Yeomans, senior research scientist at NASA’s Jet Propulsion Laboratory in Pasadena, CA, was kind enough to address some common questions regarding 2012, such as the much-misunderstood Mayan “long-count” calendar, Nibiru, pole-reversal and other such purported “doomsday” devices. Check it out.

Still set on the world ending come Dec. 21?

Back off, man. Don’s a scientist.

Can Solar Flares Hurt Astronauts?

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Solar flares, coronal mass ejections, high-energy photons, cosmic rays… space is full of various forms of radiation that a human wouldn’t want to be exposed to for very long. Energized particles traveling into and through the body can cause a host of nasty health problems, from low blood count to radiation sickness to cataracts and cancer… and potentially even death. Luckily Earth’s magnetic field and atmosphere protects us on the surface from much of this radiation, but what about the astronauts aboard the Space Station? How could events such as today’s powerful near-X-class solar flare and last week’s CME affect them, orbiting 240 miles above Earth’s surface?

Surprisingly, they are safer than you might think.

M8.7-class solar flare erupting on the Sun's northeastern hemisphere at 03:49 UT on Jan. 23, 2012. (Courtesy NASA/SDO and the AIA team. Edited by J. Major.)

The M8.7-class flare that erupted from the Sun early on Jan. 23 sent a huge wave of high-energy protons Earthward, creating the largest solar storm seen since 2005.  The cloud of energetic particles raced outwards through the Sun’s atmosphere at speeds well over a million miles per hour, blowing past our planet later the same day. (More slower-moving charged particles will impact the magnetosphere in the coming days.) We are safe on Earth but astronauts exposed to such radiation could have faced serious health risks. Fortunately, most solar protons cannot pass through the hull of the Space Station and so as long as the astronauts stay inside, they are safe.

Of course, this is not the case with more dangerous cosmic rays.

According to the NASA Science site:

Cosmic rays are super-charged subatomic particles coming mainly from outside our solar system. Sources include exploding stars, black holes and other characters that dwarf the sun in violence. Unlike solar protons, which are relatively easy to stop with materials such as aluminum or plastic, cosmic rays cannot be completely stopped by any known shielding technology.

Even inside their ships, astronauts are exposed to a slow drizzle of cosmic rays coming right through the hull. The particles penetrate flesh, damaging tissue at the microscopic level. One possible side-effect is broken DNA, which can, over the course of time, cause cancer, cataracts and other maladies.

In a nutshell, cosmic rays are bad. Especially in large, long-term doses.

Now the astronauts aboard the ISS are still well within Earth’s protective magnetic field and so are shielded from much of the cosmic radiation that passes through our solar system daily. And, strangely enough, when solar flares occur – such as today’s – the amount of cosmic radiation the ISS encounters actually decreases.

Why?

The solar particles push them away.

Decrease in cosmic radiation during a CME recorded in 2005.

In an effect known as the “Forbush decrease”,  magnetically-charged particles ejected from the Sun during flares and CMEs reduce the amount of cosmic radiation the ISS experiences, basically because they “sweep away” other charged particles of more cosmic origin.

Because cosmic rays can easily penetrate the Station’s hull, and solar protons are much less able to, the irony is that astronauts are actually a degree safer during solar storms than they would be otherwise.

And it’s not just in low-Earth orbit, either: Wherever CMEs go, cosmic rays are deflected. Forbush decreases have been observed on Earth and in Earth orbit onboard Mir and the ISS. The Pioneer 10 and 11 and Voyager 1 and 2 spacecraft have experienced them, too, beyond the orbit of Neptune. (via NASA Science.)

Due to this unexpected side effect of solar activity it’s quite possible that future manned missions to the Moon, Mars, an asteroid, etc. would be scheduled during a period of solar maximum, like the one we are in the middle of right now. The added protection from cosmic rays would be a big benefit for long-duration missions since we really don’t know all the effects that cosmic radiation may have on the human body. We simply haven’t been traveling in space long enough. But the less exposure to radiation, the better it is for astronauts.

Maybe solar storms aren’t so bad after all.

Read more about solar radiation and the Forbush decrease on NASA Science here.

Aurora Alert! Sun Sends CME in Earth’s Direction

As seen here by the Solar Dynamics Observatory, a long duration M3-class flare began erupting on the Sun from sunspot region 1401 at 13:42 UTC (8:42 AM ET) today, Thursday, January 19, 2012, sending a coronal mass ejection (CME) directly towards Earth. Scientists predict the CME will arrive at around 16:00 UTC on January 21, 2012 GMT. Spaceweather.com says strong geomagnetic storms are possible and high-latitude (and possibly middle-latitude) skywatchers can be on the lookout for increased aurora.

Continue reading “Aurora Alert! Sun Sends CME in Earth’s Direction”