Unprecedented 8 satellite view of magnetospheric substorm details and reconnection

Energy tracked from solar wind to Earth

In July 2012, scientists took advantage of a rare eight satellite conjunction across the magnetotail to gain more details of the substorm process.  Below is a depiction of of the satellites involved:

Credit:
NASA/SVS

The initial magnetic reconnection happened very quickly, in a region a couple hundred miles across.  Then, the energy was converted and moved the distance between the Moon and Earth, changing forms along the way.  The final destination was to light up the Aurora at high latitudes.

“One of the unique features of our research field is that microscopic things can sometimes run the whole show,” says David Sibeck, the project scientist for ARTEMIS and THEMIS at NASA’s Goddard Space Flight Center in Greenbelt, Md. “The tiniest causes may have global consequences."

Indeed, small events that happen for a millisecond can drive energy flows lasting up to 30 minutes and cover an area 10 times larger than Earth.

To cover such a vast region, multiple spacecraft are needed, situated at different points throughout the magnetosphere, the protective bubble created by the Earth's magnetic field within the flow of the solar wind.

Have a look at the video to get an idea of the scale we're talking about:

While much of these details have been known and modeled for some time, this is the first multi-scale in-situ measurement, and paid off with some new information about the process.

The energy that this represents is equivalent to a 7.1 magnitude earthquake.  For more details, check out the paper that was produced from the mission results:

Electromagnetic Energy Conversion at Reconnection Fronts
V. Angelopoulos, A. Runov, X.-Z. Zhou, D. L. Turner, S. A. Kiehas, S.-S. Li, and I. Shinohara
Science 27 September 2013: 341 (6153), 1478-1482. [DOI:10.1126/science.1236992]

Abstract
Earth’s magnetotail contains magnetic energy derived from the kinetic energy of the solar wind. Conversion of that energy back to particle energy ultimately powers Earth’s auroras, heats the magnetospheric plasma, and energizes the Van Allen radiation belts. Where and how such electromagnetic energy conversion occurs has been unclear. Using a conjunction between eight spacecraft, we show that this conversion takes place within fronts of recently reconnected magnetic flux, predominantly at 1- to 10-electron inertial length scale, intense electrical current sheets (tens to hundreds of nanoamperes per square meter). Launched continually during intervals of geomagnetic activity, these reconnection outflow flux fronts convert ~10 to 100 gigawatts per square Earth radius of power, consistent with local magnetic flux transport, and a few times 10¹⁵ joules of magnetic energy, consistent with global magnetotail flux reduction.


Late next year, NASA is scheduled to launch the Magnetospheric Multiscale (MMS) mission which will add one more important elelment of the reconnection process - getting a simultaneous measurement of the front side reconnection that preceeds the process shown above.

More information can be found at this NASA page:  Several NASA Spacecraft Track Energy Through Space

Are Noctilucent Clouds connected with Climate Change?

NLCs in Finland.  (c) Pekka Parviainen

NASA reported yesterday that their AIM Mission continues to add to our understanding of Noctilucent Clouds (NLC).

"The 2013 season is remarkable because it started in the northern hemisphere a week earlier than any other season that AIM has observed," reports Cora Randall of the Laboratory for Atmospheric and Space Physics at the University of Colorado. "This is quite possibly earlier than ever before."

The ScienceCast video below was posted in the STEM on Google+ Community, where the focus was aimed toward work that connects NLCs to climate change.

NLCs are cloud-like phenomena that are located near the edge of polar mesospheric clouds in the upper
atmosphere. They are made of ice crystals and are typically observed in the summer months at latitudes between 50° and 70° north and south of the equator when the Sun is below the horizon.

Their occurrence can be used as a sensitive guide to changes in the upper atmosphere.

Wikipedia pulls some of the connections together:

There is evidence that the relatively recent appearance of noctilucent clouds, and their gradual increase, may be linked to climate change.[1] The author of this study, atmospheric scientist Gary Thomas of the Laboratory for Atmospheric and Space Physics at the University of Colorado has pointed out[2] that the first sightings coincide with both Krakatoa and the nascent Industrial Revolution, and they have become more widespread and frequent throughout the twentieth century, including an uptick between 1964 and 1986. The connecting of global warming and noctilucent clouds however, remains controversial.[2]

Climate models predict that increased greenhouse gas emissions cause a cooling of the mesosphere, which would lead to more frequent and widespread occurrences of noctilucent clouds.[3] A competing theory is that larger methane emissions from intensive farming activities produce more water vapour in the upper atmosphere.[4] Methane concentrations have more than doubled in the past 100 years.[5]

One possible weakness is the timing coincidence of the first sightings.  Given the limited time of day, typical geographic location, and overall appearance of NLCs being so similar to aurora, they may have been lumped together with that phenomenon.  See photos [A, B] of recent low latitude aurora, which is also a fairly rare event.  Oddly, NLCs are anti-correlated with the peak of the solar cycle which is going on right now, and is the direct cause of the conditions that spark the aurora.

It's also curious to me that the word "competing" is used between cooling of the mesosphere and more water vapor in the upper atmosphere, as both are necessary characteristics of NLCs.
 
Relating to the last post here is the question: Is it better to push the envelope when it comes to possible connections to climate change in order to increase awareness, or is it too risky given that many people won't have adequate knowledge of varied and lessor known phenomena, and how they would relate?  The risk being that either people will dismiss these connections out of hand, or if ultimately disproved, would become fodder for denialism.


[1] Thomas, GE; Olivero, J (2001). "Noctilucent clouds as possible indicators of global change in the mesosphere". Advances in Space Research 28 (7): 939–946. 
[2] Phillips, Tony (August 25, 2008). "Strange Clouds at the Edge of Space". NASA.
[3] A. Klekociuk, R. Morris, J. French (2008). "First Antarctic ground-satellite view of ice aerosol clouds at the edge of space". Australian Antarctic Division. Retrieved 2008-10-19.
[4] "Noctilucent clouds". Australian Antarctic Division.
[5] Hsu, Jeremy (2008-09-03). "Strange clouds spotted at the edge of Earth's atmosphere". USAtoday.