NASA to Investigate Magnetic Explosions
 
March 10, 2015:  Magnetic reconnection could be the Universe's favorite way
to make things explode.
 
It operates anywhere magnetic fields pervade space--which is to say almost
everywhere. In the cores of galaxies, magnetic reconnection sparks
explosions visible billions of light-years away. On the sun, it causes
solar flares as powerful as a million atomic bombs. At Earth, it powers
magnetic storms and auroras. It's ubiquitous.
 
The problem is, researchers can't explain it.
 
https://www.youtube.com/watch?v=BGh1xc-O0WA&feature=youtu.be
 
A new ScienceCast video previews the MMS mission to study the mysteries of
magnetic reconnection. Play it
 
The basics are clear enough. Magnetic lines of force cross, cancel,
reconnect and-Bang! Magnetic energy is unleashed, with charged-particles
flying off near the speed of light. But how? How does the simple act of
crisscrossing magnetic field lines trigger such a ferocious explosion?
 
"Something very interesting and fundamental is going on that we don't
fully understand," says Jim Burch of the Southwest Research Institute.
 
NASA is about to launch a mission to get to the bottom of the mystery. It's
called MMS, short for "Magnetospheric Multiscale" and it consists
of four spacecraft that will fly through Earth's magnetic field, or
"magnetosphere," to study reconnection in action.
 
"Earth's magnetosphere is a wonderful natural laboratory for studying
this phenomenon," says Burch, the MMS Principal Investigator.
 
Slated for launch on March 12th, the four spacecraft were designed, built
and tested at NASA's Goddard Space Flight Center. Each one is shaped like a
giant hockey puck, about 4 meters in diameter and 1 meter in height.  In
space, however, they are much larger.
 
http://tinyurl.com/kbbs7ho
 
A cartoon model of magnetic reconnection on the sun. [more] "After
launch, the spinning spacecraft will unfurl their electromagnetic sensors,
which are at the end of wire booms as much as 60 meters long," says
Craig Tooley, MMS Project Manager at Goddard.  "When fully extended,
the sensors are as wide as a baseball field."
 
These sprawling, spinning probes will fly in precise formation, as close as
10 km apart and are guided by GPS satellites orbiting Earth far below them.
"We can maintain formation with an accuracy of only 100 meters,"
says Tooley. "This is crucial to our measurements."
 
Any new physics MMS observes could help provide clean energy on Earth.
 
"For many years, researchers have looked to fusion as a clean and
abundant source of energy for our planet," says Burch. "One
approach, magnetic confinement fusion, has yielded very promising results
with devices such as tokamaks. But there have been problems keeping the
plasma contained in the chamber."
 
"One of the main problems is magnetic reconnection," he
continues. "A spectacular result of reconnection is known as the
'sawtooth crash.' As heat in the tokamak builds up, the electron
temperature reaches a peak, then 'crashes' to a lower value. Some of the
hot plasma escapes. This is caused by reconnection of the containment
field."
 
In light of this, you might suppose that fusion chambers would be a good
place to study reconnection. But no, says Burch. Reconnection in tokamaks
happens in a tiny volume only a few centimeters wide. It is practically
impossible to build sensors small enough to probe the reconnection zone.
 
Earth's magnetosphere is much better. In the expansive magnetic bubble that
surrounds our planet, the process plays out over volumes as large as tens
of kilometers across, for instance, when reconnection at the sun propels
plasma clouds toward Earth, where additional reconnection events then
sparks auroras.
 
"We can fly spacecraft in and around it and get a good look at what's
going on," he says.
 
That is what MMS will do: fly directly into the reconnection zone. The
spacecraft are sturdy enough to withstand the energetics of reconnection
events known to occur in Earth's magnetosphere, so there is nothing
standing in the way of a full two-year mission of discovery.
 
For more information and updates, visit the MMS home page: www.nasa.gov/mms
 
Credits:
Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit:
Science{at}NASA
 
 
Regards,
 
Roger

--- D'Bridge 3.99