Greetings from Huntsville, Alabama!
I was in your country in 1999, for a total solar eclipse. Our group went to Rimnicu Valcea. My one regret is that I did not stay longer to see more of Romania; it is a beautiful country. I will tackle a few of your questions...they are great ones, by the way.
1. What kind of data can be implied about the inside of the Sun by
analyzing the disturbances at its surface?
There is a field of study, called helioseismology, that analyzes the oscillations of the surface to infer conditions in the interior. It essentially works in the same manner as seismology on Earth. My colleague, Dr. David Hathaway, has written a web page that you might find interesting. On this page, he includes links to movies that illustrate how one can use the surface distrbances to learn more about the Sun. He refers to the GONG network, which is the Global Oscillation Network Group. You will find a link to GONG as well.
http://solarscience.msfc....elioseismology.shtml2. How can the enormous differences of temperature at the surface
of the Sun be explained?
The surface of the Sun, the photosphere, is essentially at one temperature, approximately 6000 Kelvin. However, sunspots are approximately 2/3 that value and are cooler because their strong magnetic fields suppress convection from below. As one travels higher into the solar atmosphere, things get interesting. The temperature in the chromosphere actually increases, reaching a maximum of approximately 20,000 Kelvin. Then higher into the corona, the temperature reaches millions of degrees! This increase in temperature, as one moves farther away from the energy source (fusion reactions in the core of the Sun), is indeed counter-intuitive and remains an unsolved mystery. One explanation is that nano-flares or micro-flares heat the corona through magnetic reconnection, but the theorists calculate that there's not enough energy. Waves can explain some of the heating, but as of today, no one theory has been able to account for the temperature changes through the solar atmosphere.
4. How long will it take until we will be able, with the future
equipment, to discover the Sun's surface in detail, having no distance
restrictions?
Our instrumentation continues to improve, giving us better and better resolution of the Sun. For example, the solar probe Hinode has one arcsec pixels, which means that we can resolve features that are about 725 km. SOHO's MDI, an older mission, has 1.25 arcsec pixels. The next generation of instruments will attempt even better resolution. A new mission, called Solar Probe, will actually fly into the solar corona! You can find a description here: http://solarprobe.gsfc.nasa.gov/
Another of my colleagues, Dr. Jonathan Cirtain, has recorded a bit about this mission here: http://www.nasa.gov/multi...ml?media_id=19197261
You might find this interesting: http://eo.nso.edu/. Toward the bottom of the page, are links to classroom research activities.
Cheers,
Mitzi Adams