Watching the Solar Wind Blow By
by Lea C.
1st Place - Engineering

Question: Does the Sun’s IMF (Interplanetary Magnetic Fields) ever change? Can we see the changes in Van Nuys?
I wondered if it was possible to measure the changes in the sun’s magnetic field from the ground. Is it strong enough to be measured? Would the earth’s magnetic field get in the way? Would it be possible to build a home made detector of magnetic fields? Would my measurements show changes over time?

Research: I began to explore the idea of solar wind when I discovered that it was the particles they carried from the sun that caused the Northern lights. The Sun’s corona boils off a stream of electrons & protons that goes out into space at about a million miles per hour. This is amazingly fast. It’s like traveling more than half the length of California in about 2 seconds. They call these fast moving particles the Solar wind. It’s like a river that changes with the sun’s every blip and burp. Some parts are thicker and some are faster. The Solar wind eventually passes earth’s orbital distance. Some of this material washes over the earth. IMF or Interplanetary Magnetic Field is the solar wind’s magnetic field. As this magnetic field washes over the earth it’s effects stretch through the atmosphere.

Hypothesis: My hypothesis is that IMF does change with time.

Experiment:
Step 1 – Building a Magnetometer. Materials: Laser pen, batteries, nylon filament, sewing needle, 2 clear plastic jewel – style CD case, 4 earth magnets, plastic mirror sheet, 4 spring style clothes pins, 4 ceramic disk magnets, 2 index cards, measuring tape, 2 Quadra pole magnets, toothpicks, 4 popsicle sticks, 2 pairs disposable gloves, tweezers, ruler, epoxy resin & hardener, instructions. I followed instructions found in the internet for making a homemade magnetometer.
Step 2 – Set up. The biggest challenge in setting up was finding a location that worked. It had to be in a place where it would not be disturbed during data collection. So that I am measuring just the changes in the magnetic field from the Solar winds, I must cancel out anything that might make the sensor magnets move. All magnets make their own magnetic field and currents called eddy currents. To cancel out the sensor magnets’ eddy currents, I glued a true copper penny (older than 1965) to the cd case behind the sensor magnet. To cancel out the earth’s magnetic field, I used 4 nulling magnets. These are 4 strong magnets that I glued to another cd case. I placed this case near the sensor magnets to a point where it hangs freely without being pulled to face north. At this point the earth’s magnetic field is cancelled out. Now, only the movement from the solar wind is detected. Calibration of the sensing magnets showed that I was measuring 1mm = 1nT (nano Tesla). The Tesla is the unit for measuring the strength of a magnetic field. It is named after Nikola Tesla. One Tesla is about 20,000 times the magnetic field of the earth. A nano Tesla is one billionth of a Tesla
Step 3 – Data Collection To measure fluctuations, a laser pointer is pointed at the Mylar on the sensor magnet and reflected onto a wall about 4 yards away. Any movement is easily seen as the laser’s reflected light moves on the wall. To record these movements, I taped a ruler on the wall with the starting point marked by a dark line. I recorded the movements at 30 minute intervals, 15 minute intervals and 5 minute intervals, for a period of one to two hours.

Analysis:
The magnetic field is always shifting. My data confirms this. I was able to note changes even every 5 minutes. Once I made my observations, I compared them to the data on line from the NASA ACE Satellite that measures Solar Wind. I was not expecting to see the same data as the satellite. I did observe similar changes. Spikey structures stayed spikey. Major changes in the satellite data also showed in my data. It was especially noted on the data collected on Mar. 9th, where I was able to collect over a longer period of time, every 5 minutes. All the shapes and structures arrived in the same order as the ACE data and all the changes shifted in roughly the same amount of time.

Discovery:
It was a relief to begin the experiment and see measurable changes from the start. I had doubts that my homemade magnetometer would work. I am impressed that such a simple tool could measure with such accuracy and show about same results as the ACE satellite. I learned that the earth is a giant magnet and there is more than just air floating around us. There are magnetic fields everywhere and from many sources.

Bigliography:
Anonymous. NASA–Student Observation Network, <www.nasa.gov/audience/foreducators/son/home/index.html>
Anonymous. ACE Satellite <http://www.swpc.noaa.gov/ace/ace_rtsw_data.html>
Anonymous. Solar Wind, Wikimedia, Inc.< http://en.wikipedia.org/wiki/Solar_wind>
Anonymous. Sun-Earth Viewer <www.sunearth.gsfc.nasa.gov/sunearthday/media_verwer/flash.html>