From the American Physical Society News from the 2014 APS Division of Plasma Physics Meeting
Each second, the sun hurls millions of tons of hot, charged plasma gas into space. This volatile “solar wind” buffets the magnetosphere, the magnetic field that surrounds the Earth, and can whip up geomagnetic storms that disrupt cell phone service, damage satellites and blackout power grids. Precise predictions of such outbursts could prompt measures to cope with them, just as forecasts here on Earth warn of approaching hurricanes and thunderstorms.
Researchers throughout the United States are using laboratory experiments to uncover important physics behind this space weather. Their latest results will be presented at the annual meeting of the American Physical Society’s Division of Plasma Physics in New Orleans. Among their findings:
- Experiments at Princeton Plasma Physics Lab show in detail how magnetic reconnection, an explosive phenomenon that occurs in solar flares near the sun, accelerates solar wind particles to high energy, and how the resulting solar wind interacts with the magnetic field that shields the earth.
- Using a plasma “wind tunnel” at Swarthmore College, professor Michael Brown and post doc David Schaffner are now able to simulate the key signatures of magnetic turbulence seen in the solar wind and expected to play a role in astrophysical jets driven by exploding stars.
- A team of scientists on the Large Plasma Device (LAPD) at UCLA has recorded laboratory observations of interactions between plasma magnetic waves. These waves are known to ripple through the turbulent solar wind where theory and satellite measurements suggest the observed interactions may help explain the behavior of the hot plasma.
- Columbia University graduate student Thomas Roberts and his advisor, using a chamber filled with plasma and magnetic fields simulating the earth’s magnetosphere, have discovered a possible connection between ionospheric currents and local space weather near the earth.
Following are key results of five leading studies of physical processes that researchers have conducted in the laboratory to understand what happens in space, where the ability to make measurements is far more limited.
HOW MAGNETIC RECONNECTION GOES “BOOM!”
Magnetic reconnection, in which the magnetic field lines in plasma snap apart and violently reconnect, creates massive eruptions of plasma from the sun. But how reconnection transforms magnetic energy into explosive particle energy has been a major mystery.
Now scientists at the U.S. Department of Energy’s (DOE) Plasma Physics Laboratory (PPPL) have taken a key step toward solving the mystery. In research conducted on the Magnetic Reconnection Experiment (MRX) at PPPL, the scientists not only identified how the transformation takes place, but measured experimentally the amount of magnetic energy that turns into particle energy. This work was supported by the DOE Office of Science.
The investigation showed that reconnection in a pro-typical reconnection layer converts about 50 percent of the magnetic energy, with one-third of the conversion heating the electrons and two-thirds accelerating the ions — or atomic nuclei — in the plasma. In large bodies like the sun, such converted energy can equal the power of millions of tons of TNT.
“This is a major milestone for our research,” said Masaaki Yamada, the principal investigator for the MRX. “We can now see the entire picture of how much of the energy goes to the electrons and how much to the ions in a prototypical reconnection layer.”
Contacts:
M. Yamada myamada@pppl.gov, 609-243-2566
J. Yoo jyoo@pppl.gov, 609-243-2192
Related APS Talks:
Invited talk M. Yamada (DPP14-2014-000322)
Experimental study of energy conversion in the magnetic reconnection layer
Session BI2: Space, Astro, and Lab Astr
11:30 AM-12:00 PM, Monday, October 27, 2014
Bissonet
Energetics of the magnetic reconnection in laboratory and space plasmas, by M. Yamada Session JM10: Mini-Conference: The Magnetic Universe
2:00 PM Tuesday, October 28, 2014
Salon FGH
The talk will be presented from 4:40 PM to 5:00 PM
WHAT A DIFFERENCE A MAGNETIC FIELD MAKES
Spacecraft observing magnetic reconnection have noted a fundamental gap between most theoretical studies of the phenomenon and what happens in space. While the studies assume that the converging plasmas share symmetrical characteristics such as temperature, density and magnetic strength, observations have shown that this is hardly the case.
PPPL researchers have now found the disparity in plasma density in experiments conducted on the MRX. The work, done in collaboration with the Space Science Center at the University of New Hampshire, marks the first laboratory confirmation of the disparity and deepens understanding of the mechanisms involved.
The research replicated at small scale the convergence of the plasma in solar wind and the plasma-filled magnetosphere, or magnetic field that surrounds the Earth. Before convergence, the density of the solar wind-like plasma was found to be from 10 times to 100 times greater than the density of the plasma that represented the magnetosphere.
Data from the MRX findings could help to inform a four-satellite mission — the Magnetospheric Multiscale Mission, or MMS — that NASA plans to launch next year to study reconnection in the magnetosphere. The probes could produce a better understanding of geomagnetic storms and lead to advanced warning of the disturbances and an improved ability to cope with them.
Contact:
J. Yoo jyoo@pppl.gov, 609-243-2192
Abstract:
PP8.00106: Studies of electron energization during magnetic reconnection in a laboratory plasma
Session PP8: Poster Session VI: MST and Other Reversed Field Pinches;
NSTX and Other Spherical Tori; Magnetic Reconnection
2:00 PM–5:00 PM, Wednesday, October 29, 2014
Preservation Hall
BRINGING WAVES IN SPACE PLASMAS DOWN TO EARTH
To make forecasts of space weather a reality, scientists must first understand the plasma processes that occur on the sun’s surface and between the Earth and the sun. In particular, understanding the interaction between waves that course through the plasma may play a key role in explaining how the overall sun-Earth system behaves.
Scientists at the Large Plasma Device (LAPD) at UCLA have made the first laboratory observations of two potentially important wave-wave interaction processes. Both involve the most fundamental wave that exists in a plasma with a magnetic field. These waves, known as Alfvén waves, can be thought of as if the magnetic field were plucked like a string. The new LAPD observations enhance our understanding of fundamental physical processes that may play a key role in explaining how plasma behaves in space.
The wave-wave interactions observed have been predicted by theory and suggested by satellite observation, but have never before been seen in the laboratory.
UCLA scientists contributing to this work include: Seth Dorfman, Troy Carter, Stephen Vincena, Patrick Pribyl, Danny Guice, and Giovanni Rossi. Collaborators from other institutions include: Richard Sydora at University of Alberta, Yu Lin at Auburn University, and Kristopher Klein at University of New Hampshire.
Contact:
Seth Dorfman, sethd@physics.ucla.edu
Abstract:
DI2.00002 Laboratory Studies of Nonlinear Interactions Relevant to Alfvén Wave Decay Instabilities
3:30 PM–4:00 PM, Monday, October 27, 2014
Bissonet
CAPTURING A PIECE OF THE SOLAR WIND
The turbulence in solar wind twists and tangles magnetic field lines and can give rise to magnetic reconnection and stormy space weather. At Swarthmore College, the Swarthmore Spheromak Experiment (SSX) serves as the world’s first plasma wind tunnel and recreates conditions similar to those found in the solar wind.
Research conducted under Prof. Michael Brown creates one-million-degree plasmas that sweep through the SSX at more than 60 miles per second. Working with post-doctoral fellow David Schaffner, the scientists have explored the mysteries of magnetohydrodynamic (MHD) — or magnetic fluid — turbulence. Their findings have enhanced understanding of the solar wind turbulence that can affect satellites and influence the environment of space near the Earth.
Combining all the measures of turbulence that the laboratory has developed could lead to a framework that captures the characteristics of all plasma turbulence — whether in fusion devices, laboratory MHD plasmas or the plasmas in outer space.
Contact:
David Schaffner, dschaff2@swarthmore.edu
Abstracts
PT2.00001: Magnetohydrodynamic Turbulence: Observation and Experiment
2:00 PM–2:30 PM, Wednesday, October 29
Bissonet
Session PT2: Tutorial: Magnetohydrodynamic Turbulence: Observation and Experiment
2:00 PM–2:30 PM, Wednesday, October 29, 2014
Bissonet
TP8.00067 : MHD turbulence analyses in the plasma wind-tunnel of the Swarthmore
Spheromak Experiment
9:30 AM–9:30 AM, Thursday, October 30, 2014
Preservation Hall
Session TP8: Poster Session VII: C-MOD TOKAMAK; Divertors; Boundary/Edge
Physics; Heating and Drive; Turbulence, Transport and Astrophysical Plasmas
9:30 AM–9:30 AM, Thursday, October 30, 2014
Preservation Hall
JP8.00017 : Permutation entropy analysis of dynamical turbulence in the SSX MHD wind tunnel and the solar wind
2:00 PM–2:00 PM, Tuesday, October 28, 2014
Preservation Hall
Session JP8: Poster Session IV: Education and Outreach; Undergraduate/High School Research; Fundamental Theory and Computation; Magnetic ICF & HEDP; Z-Pinch, X- Pinch, Exploding Wire Plasma and Dense Plasma Focus
2:00 PM–2:00 PM, Tuesday, October 28, 2014
Preservation Hall
TAMING TURBULENT SPACE WEATHER IN A LABORATORY MAGNETOSPHERE
Like the lighting that bolts from storms clouds, powerful currents flow toward Earth from the motion of plasma that takes place inside the magnetosphere. Now students and scientists at Columbia University have conducted the first controlled experiments that regulate currents extracted from a fast-moving laboratory plasma contained by a magnetic field shaped like the field in the Earth’s magnetosphere.
This research gives students a new tool to test space-weather models, and provides clues to controlling the turbulence that causes heat and particles to escape from magnetic confinement in fusion facilities.
To reduce turbulence in the laboratory plasma, the students used an electrode to extract current from the plasma. Reversing the process by injecting current amplified the turbulence.
The experiments paralleled the process that takes place in space when the current that flows from magnetospheric plasma through the Earth’s ionosphere slows the motion of space plasma. Adjusting the current thus acts like turning a knob to regulate the turbulence — a finding that could enhance the performance of future fusion facilities.
Contact:
Thomas Max Roberts, tmr2122@columbia.edu
Mike Mauel, 212-854-4455, mauel@columbia.edu
Abstract:
Invited Presentation N12.00001
Author: Thomas Max Roberts
Title: “Local Regulation of Interchange Turbulence in a Dipole-Confined Plasma Torus using Current-Collection Feedback
9:30 AM-10:00 AM, Wednesday, Oct. 29
Bissonet
lsvalgaard October 29, 2014 at 1:30 pm
The electron orbitals are not electric currents.
Cherry picking. It was said:
“electrons orbiting the nucleus with a spin”
As you well know but prefer not to mention it is the spin that gives an electron its magnetic momentum!
Magnetism is an effect and as such it is transitory. Electrons and protons, charged particles, the substance of the earliest universe have been around ever since, a sure sign of their permanence.
To generate or observe magnetic effect PRESENCE of CHARGED PARTICLES is required; without charged particles magnetism can not be generated, without charged particles magnetism can not be observed. Electric charges are both the mother and the father of any and all magnetism.
Study Parker’s paper carefully http://press.princeton.edu/chapters/s8454.pdf before you make a further fool of yourself.
And it is magnetic moment, not magnetic momemtum.
At my university, some decades ago it was known in my native language as ‘magnetic momentum’, so I used it as such, but if caused an ambiguity ‘magnetic moment’ is just fine.
Eugene N. Parker is a astrophysicist. Anyone who has never trained as an electric or electronic engineer and spent working life dealing with electric currents could be forgiven for being mixed up about electric currents and magnetism.
James Clerk Maxwell should be your reference (at my uni was a 2 year course).
Maxwell is all about dynamics, astrophysicists talk about frozen magnetism, there is no such thing.
Anyone who has never trained as an electric or electronic engineer and spent working life dealing with electric currents could be forgiven for being mixed up about electric currents and magnetism.
I understand your confusion. You are also confused about charge and current. Every breadth you take contains something like 10^25 charged particles, but [hopefully] no electric currents.
Parker said it best:
“we are interested here in the electromagnetism of the cosmos—the large-scale magnetic fields that are transported bodily in the swirling ionized gases (plasmas) of planetary magnetospheres, stars, and galaxies, and, indeed, throughout intergalactic space. The plasma and the magnetic fields appear to be everywhere throughout the universe. The essential feature is that no significant electric field can arise in the frame of reference of the moving plasma. Hence, the large-scale dynamics of the magnetic field is tied to the hydrodynamics (HD) of the swirling plasma in the manner described by theoretical magnetohydrodynamics (MHD). So we shall have a fresh look at the theoretical foundations of both HD and MHD. The conventional derivations of the basic equations of HD and MHD are correct, of course, but the derivations ignore some fundamental questions, allowing a variety of misconceptions to flourish in the
scientific community. We work out a minimal physical derivation, laying bare the simplicity of the necessary and sufficient conditions for the validity of HD and MHD to describe the large-scale bulk motion of plasmas and their magnetic fields. The essential condition for HD is that there be enough particles to give a statistically precise definition of the local plasma density; the essential condition for MHD is that there be enough free electrons and ions that the plasma cannot support any significant electric field in its own
moving frame of reference. Both of these requirements are satisfied almost everywhere throughout the cosmos, with the result that HD and MHD accurately describe the large-scale bulk dynamics of the plasmas and fields. The magnetic field is transported bodily with the bulk motion of the plasma, and the dynamics is basically the mechanical interaction between the stresses in the magnetic field B and the pressure and bulk momentum density of the plasma velocity. The associated electric current j and the electric field E in the laboratory frame of reference play no direct role in the dynamics. They are created and driven by the varying B and v. If needed for some purpose, they are readily computed once the dynamics has provided B and v.”
They are created and driven by the varying B and v.
So called ‘frozen-in’ magnetic field would have a constant B, and not varying B !
I here by abandon you and your magnetic freezer.
Your attempt to flaunt your ignorance falls, as usual, a bit flat, although it is good you stop wasting our time anymore.
Since the magnetic field is frozen into the plasma, it follows the plasma, so, if the plasma is compressed [e.g. by high-speed plasma plowing into slower plasma ahead of it] the field will be compressed too and B will increase accordingly. For the unwashed masses the frozen-in field may perhaps best be grasped by considering the spiral magnetic field lines in the radially expanding plasma, e.g.
http://www.keelynet.com/spider/magfield.gif
” For the unwashed masses the frozen-in field may perhaps best be grasped by considering the spiral magnetic field lines in the radially expanding plasma, e.g.”
Leif, as being one of the unwashed, can you help me understand the frozen in magnetic field in plasma? How can magnetic field be “frozen in” into plasma?
For a permanent magnet the understanding is that the individual atoms are aligned. Plasma does not have atoms but charged particles. How are these keeping “frozen in” magnetic field? Do these run in circles? Or do these spin? Is the “frozen in” understood as created by spinning charged particles?
What does keep the particles aligned to spin all the time the same way inside the plasma flows?
Was it possible to simulate in laboratory a frozen in magnetic field in plasma, and how long was it frozen?
Lars, it is sometimes difficult to give a hand waving explanation. Here is a more rigorous one:
http://solarphysics.livingreviews.org/open?pubNo=lrsp-2005-7&page=articlesu2.html
Perhaps it is enough to point out that the frozen-in field lines are an observed reality, e.g. the field in the solar wind have a spiral shape.
It is important to note that in certain circumstances the frozen-in condition can be broken and interesting things [such as dissipative electric currents – ‘explosions’] can happen.
“so, if the plasma is compressed [e.g. by high-speed plasma plowing into slower plasma ahead of it] the field will be compressed too and B will increase accordingly. ”
“The solar wind is a hot and fast flow of magnetized gas that streams away from the sun’s upper atmosphere. It is made of hydrogen and helium ions with a sprinkling of heavier elements. Researchers liken it to the steam from a pot of water boiling on a stove; the sun is literally boiling itself away.
“But,” says Adam Szabo of the NASA Goddard Space Flight Center, “solar wind does something that steam in your kitchen never does. As steam rises from a pot, it slows and cools. As solar wind leaves the sun, it accelerates, tripling in speed as it passes through the corona. Furthermore, something inside the solar wind continues to add heat even as it blows into the cold of space.””
http://science.nasa.gov/science-news/science-at-nasa/2013/08mar_solarwind/
Isn’t acceleration a form of freefall ? Doesn’t freefall stop the moment you plow into something ?
As solar wind leaves the sun, it accelerates, tripling in speed as it passes through the corona.
The speeding up is [counter intuitively] due to gravity. Gravity usually hold something back when you throw it up, but because gravity decreases with height that restriction is gradually relaxed and the speed increases. The effect is the same as in a deLaval rocket nozzle http://en.wikipedia.org/wiki/De_Laval_nozzle
But how can it accelerate when it is plowing into slower plasma ahead of it.?
Here’s a couple of links that may help create understanding
http://www.physicsclassroom.com/class/estatics/Lesson-3/Coulomb-s-Law
http://link.springer.com/article/10.1023%2FA%3A1026775408875
Leif Svalgaard
October 29, 2014 at 12:55 pm
“No, the Biermann Battery Effect only created the first magnetic fields eons ago….”
“Now, the BB-effect may not be the only mechanism that can produce seed fields, but its importance lies in the fact that it showed that such production was possible.”
So when you use this “BB-effect” (big bang-effect) to make your point, you are using an unproven theory about eons ago to support your view, yet you immediately say “No” when I use a proven theory to make my point, even tho you appear to agree!
I’ll remind you again, the mass of a star produces its polar field by way of E=mc2.
I suppose the only way you can change this fact is by changing the theoretical properties of the early universe. Nice try Leif.
As usual, I have no idea what you are talking about. By Bb-effect I obviously meant the Biermann-Battery effect. Your E-nc2 bit is plain nonsense. And the Big-Bang is very well supported by evidence [but irrelevant to the topic].
You know very well my “big bang effect” is humor directed at your unfalsifiable belief that magnetic fields are remnants left over from the big bang. “the Biermann Battery Effect only created the first magnetic fields eons ago….”
Leif: Serous question re the big bang which I have factiously said was actually a very tiny bang.
What do the cosmologists believe was the order of magnitude of the total energy involved in the big bang’ or is that even a meaningful concept at a near point singularity ?
Is the total energy in the present universe, just what “appeared” at the BB instant, or is that also a meaningless concept ?
I guess Hawking is disturbed by the notion of a point singularity. Not happy about it myself.
Sparks: unfalsifiable
No, this is very falsifiable. See http://www.leif.org/EOS/0009061-Cosmic-Magnetic-Fields.pdf
“We argue that the most promising way to test this hypothesis is to look for possible imprints of magnetic fields on the temperature and polarization anisotropies of the cosmic microwave background radiation (CMBR). ”
george: Is the total energy in the present universe, just what “appeared” at the BB instant,
The total energy in the universe is and has always been exactly zero.
If the sun is such a nuisance, can’t we find a way to remove it, or at least turn it off?
Yep, that constant heating element, how do you dump all that heat ?
Maybe that should be the question ?
“””””…..This research gives students a new tool to test space-weather models, and provides clues to controlling the turbulence that causes heat and particles to escape from magnetic confinement in fusion facilities.
To reduce turbulence in the laboratory plasma, the students used an electrode to extract current from the plasma. Reversing the process by injecting current amplified the turbulence……”””””
So what material will they use for their turbulence stabilizing probe, in a fusion reactor with the plasma at hundreds of millions of degrees ??
Just asking.
A counteracting element.
lsvalgaard
October 31, 2014 at 11:24 pm
I cant even repeat the actual quote for fear of being struck by lightening by Leif.
What you are suggesting to me is to believe in your version of ‘god and entertain your fantasy. I will decline the offer.. I don’t believe in your BS about the universe. It’s your problem dude deal with it.
Well, your willful ignorance is not really my problem, but you directing your ‘humor’ my way is. And I have dealt with it by letting you know that.