Arriving at the observatory

We drive most of the way to the Kjell Henriksen Observatory outside of Longyearbyen in a rental car. We have to park the car by a mine, and then take the belt-wagon up the hill to get to the observatory. The ride is fun--different, but fun.

It is snowing now, so we spent most of the time working in the observatory getting all of our communications set up. Tomorrow I will take the camera up with me and get a picture from the observatory. Photo by Philip Fernandes.

Arrived in Svalbard

I am currently in Svalbard Norway, an island in the Spitzbergen Archipelago. We are up here getting ready to launch a NASA sounding rocket. This view is looking across the valley towards the hills on the far side. This is a 2 second exposure; it is pretty dark unless your eyes are dark adapted. The lights on the right side of the picture are from a coal mine. Our observatory is up the hill from this mine. I am going there for the first time later today, so I will report in on what I find in the next post.

Active again in Norway

I am up in Norway, getting ready to support a NASA sounding rocket launch. Our group at the Air Force Academy made an instrument that is flying on the Renu rocket. You can look here to get a little background on the rocket. I am traveling to Svalbard Island, and when I get there I will post more about our effort.

Hunting sprites

Well we are now out of the frozen north, and down at Langmuir Laboratory in Socorro New Mexico. We are looking for sprites using our high speed camera. I will try to post a summary of the Toolik experiment, and introduce the sprite work later this week.

Waiting for the weather to clear

Unfortunately it has been snowing a good bit here. We had clear skies Wednesday evening, but the aurora was very quiet. Thursday and Friday night it snowed. Today I walked up to the mailbox on the haul road. We typically leave candy bars in the mailbox, and the truckers will stop, take the candy bars, and leave us yesterday's paper which they bring up with them on the haul road from Fairbanks. Today I left them a snickers bar as you can see.

It is finally starting to clear off today. As I walked up, the sun was hitting the Brooks range, so I have included that picture as well. The light here is really fantastic, and is constantly changing. Yesterday we had pretty much white out conditions, but today we have a bit of sun to the south. Hopefully it will finish clearing, and we will be able to get some observing in.

Other research around camp

It started clearing off today, so hopefully we will get some decent data tonight. Since the weather was turning nice, I decided to walk around and see what other research is going on. I found UAF graduate student Laura Brosius drilling holes in the 4.5 ft thick ice that covers Toolik Lake. A picture of her and Shelby, who is a staff member at the station, lifting the ice auger out of the hole they drilled in the ice is shown to the right. Laura works for Dr. Katey Walter, who is in the Water and Environmental Research Center at UAF. Their work has to do with methane gas that comes out of lakes in Alaska and Russia caused by thawing permafrost and other mechanisms. Meeting other scientists and finding out what they do is half the fun of these field expeditions.

First results

We had snow last night and it is still snowing today, so I sat down and analyzed some of the high speed photometer data from Monday evening. The Interplanetary Magnetic Field (IMF) was nicely southward from about 04-08 UT, see the attached plot from the ACE website.

The ACE spacecraft is between the Earth and the sun, and measures the IMF orientation, as well as the solar wind speed and density. When the IMF is southward, it can "cancel" out the magnetic field of the earth which points northward. Magnetic fields can store energy (inductors are an example of this), and when the Earth's magnetic field "reconnects" with the IMF, some of the magnetic field energy is released into kinetic energy of the particles. This increase in kinetic energy results in increased aurora.

It turns out that the energy is not distributed evenly around the auroral oval when the IMF turns south. Rather, the most likely place to see an increase in auroral activity is on the opposite side of the earth from the sun. At Toolik Lake magnetic midnight is about 11:30 UT, so the aurora we were looking at was pre magnetic midnight.

At around 08:00 UT on Monday 4 March 2008, we were looking at a quiet arc that was in the magnetic zenith. The magnetic zenith is the location where the magnetic field comes straight into the Earth. At Toolik this happens at about 203 degrees Azimuth (with 0 degrees being magnetic north), and 80 degrees elevation. This means we were looking straight up the magnetic field line.

We took regular fram rate (30 frames a second) video with a Watec Supreme camera that is not intensified, as well as high speed video with a Phantom 7 camera with a VideoScope intensifier. Additionally we had a 16 channel multi anode photometer from Hamamatsu that we digitize at 20,000 samples per second. This photmeter is an easy way to look for high speed flickering in the aurora. We take the digitized time series output of the photometer, and turn it into a spectrogram, which shows power at different frequencies as an image.

The spectrogram shown to the right comes from pixel number 8 (the center pixel in the linear array of 16 pixels). The data were taken at 0801UT. The top panel in the image shows the digitized output, while the bottom panel shows the spectrogram. In the spectrogram, increasing frequency in Hertz is long the y axis, while time runs along the x axis. the color bar is in dB, with reds and yellows being higher power than blues. As you can see, there is quite a bit of power down around 5-10 Hz. In the first ~15 seconds of the spectrogram, there is also power at higher frequencies, 50-80 Hz. The eye can detect frequencies up to about 10-15 Hz, so the lower frequencies are what are seen by the eye in the Watec images.

Each file is 30 seconds long, and takes the computer a bit over 30 seconds to write to disc. So the next file was about a minute later at 08:03 UT. The spectrogram for channel 8 is shown to the left, and you can see the higher frequencies have disappeared, leaving the lower "narrow band tone" at around 8-9 Hz. A little later in the spectrogram the higher frequencies are seen again, but weaker than they were in the first spectrogram.

This is very similar to what Hans and I published in a Geophysical Review Letters article back in 1998.

We hope to obtain optical observations of flickering aurora at the same time that Jim LaBelle's Dartmouth group measures radio frequency auroral roar.