# Solar wind interaction with Earth's magnetic field

1. May 1, 2012

### jubby

I'm currently doing a project on how the solar wind interacts with the Earth's magnetic field, but I'm having a hard time grasping the concept of the plasma emitted by the Sun and how it shapes the Earth's magnetic field. I read somewhere about a simple mirror dipole approximation (I'm guessing two magnets repelling one another) and that may be the easier way to see the Earth's field getting reshaped (smashed), but I don't know where I can get the equations to mathematically understand that.

A lot of the books I'm reading discuss the pressure exerted by the solar wind, but it doesn't make sense as how that affects the magnetic field in general. Right now this is my most likely incorrect understanding:

1. Solar wind travels from Sun to Earth at v = 400 km/s (plasma = mixture of charged particles)

2. Solar wind hits barrier/obstacle (Earth)

3. Front end (noon side) is smashed, while back end (night side) is elongated (magnetic tail)

4. There exists a magnetopause (~15 Earth radii) where the solar wind simply just flows around)

What exactly is happening? Is the solar wind compressing the magnetosphere at the magnetopause? Is this compression "smashing" the magnetic fields within to reshape it into this funny-oblong shape? Is there a simple way of understanding/interpretting this phenomena? Any help would be much appreciated.

My professor also said to try have an infinite charge sheet advance to magnetic field, but I'm not sure what that exactly means. My model as of now is the simple dipole model of Earth's magnetic field (static), so I'm not sure if the shaping is time-dependent or if there's someway I can just get it at a snapshot.

Again, thank you, and yes, thank you if you can help. And if not, thanks for reading, and maybe pass it on to someone else who may help? =D

2. May 1, 2012

### Bobbywhy

jubby, Welcome to Physics Forums!

I guess you have already done the “obvious” and entered Google using the search term “magnetosphere” Google is your freind. You must learn to use it as a valuable resource to learn. If you do, you will immediately notice on the first page that comes up “Images for magnetosphere”, which are great for visualizing the interaction of the solar wind with the earth’s magnetic field. Yes, the solar wind does "compress" or "distort" the earth's magnetic field. As for your other question, I suggest you try to use Google and the search terms "infinite charge sheet magnetic field" and see what you can find.

Then there are these two sites which provide great information:

http://helios.gsfc.nasa.gov/magnet.html

http://en.wikipedia.org/wiki/Magnetosphere

After those sites, if you are interested in some actual research, you can read some technical papers at:
http://lanl.arxiv.org/find/all/1/al...1/0/all/0/1?skip=25&query_id=3878462e495f25a3

Three examples:

"Organization of the magnetosphere during substorms"
Authors: Tatjana Zivkovic, Kristoffer Rypdal
arXiv:1105.5005[pdf]

"Modeling the Young Sun's Solar Wind and its Interaction with Earth's Paleomagnetosphere"
Authors: M. Glenn Sterenborg, Ofer Cohen, Jeremy J. Drake, Tamas I. Gombosi
arXiv:1102.0003[pdf]

Title: "Solar wind triggering of geomagnetic disturbances and strong (M>6.8) earthquakes during the November - December 2004 period"
Authors: G. Anagnostopoulos, A. Papandreou, P. Antoniou
arXiv:1012.3585 [pdf]

3. May 13, 2012

### jubby

Thank you so much, Bobby. Your advice, along with countless others outside of class, had helped me shape my project to something decent and doable. I was able to somewhat plot the magnetic dipole (simple) of Earth's magnetic field, but the solar wind seemed to not be as...merciful. Instead, at the suggestion of a substitute professor whom I received lots of help a week and a half the final project was due, I went with tracking particles in certain regions of Earth's magnetic field (the Van allen radiation belt)--and ironically AFTER presenting what I was able to do, I finally actually was able to observe the path of a trapped particle in these regions (proton in the inner belt, and electron in the outer belt). My dipole didn't match the path though, so I might look into it a little more, but as expected, the particle travelled from one pole to the other (except it when it neared the poles--then it flung off into space or something--that or my program needed to be more precise). Overall, I thought it was pretty successful. If you wanted to see the codes (mainly the dipole because when mapped, it's kind of tilted--and although that would be ideal with the earth's tilt and the magnetic fields tilt with that--it was not intentional).

Again, thank you so much! Have a great summer!

4. May 13, 2012

### Bobbywhy

jubby, thanks for your feedback and for making my day! Congrats. on a successful project.

When I was looking into Alfven waves and Langmuir waves I ran into a couple of authors who seem to be doing just what you are up to:

Robert L. Lysak and Yan Song, at (I think, at the U. of Minnesota) They seem to do a lot of actual measurement as opposed to modelling.

Have a good Summer, too!
Bobbywhy