SOLAR PHYSICS

'Solar physics' is the study of our Sun. It involves creating models of the Sun, and then testing them against experimental data. Solar physics requires that measurements be made of the Sun from both Earth and orbit.
= Basic Solar physics =

Contents

Temperature of the Sun

Pioneer 6, 7, 8, and 9

Helios probes

Ulysses

Solar and Heliospheric Observatory (SOHO)

Temperature of the Sun

Given the luminosity of Sun, calculating the approximate temperature is trivial. Given the temperature dependent equation for luminosity,



$L\_\{odot\}=sigma\; T^4\; 4\; pi\; \{R\_\{odot\}\}^2$



solve for T.







Given that $L\_\{odot\}=3.846\; imes10^\{26\}\; hbox\{\; W\}$, and that $R\_\{odot\}=6.960\; imes\; 10^8\; hbox\{\; m\}$ then,



$T\_\{odot\}\; =\; 5777.5\; hbox\{\; K\}$




It is also possible to derive the temperature of the Sun by looking at its blackbody radiation spectrum. Looking at the spectral irradiance of the Sun at each wavelength and then fitting the curve to the ideal blackbody curve for a given temperature.
= Solar Probes =
One of the best ways to study solar physics is by satellite, as the instrument does not have the atmosphere to block certain extreme wavelengths, such as X-rays and Ultraviolet rays. Throughout its history, NASA has sent several probes to study the Sun.

Pioneer 6, 7, 8, and 9

Main articles: Pioneer 6, 7, 8 and 9

The first satellites to study the Sun were Pioneer 6, 7, 8, and 9. The first, Pioneer 6, was launched on December 16 1965. These satellites formed a ring around Earth of solar weather satellites used to monitor solar active for various uses. These satellites did little to study the actually mechanism of solar physics, but was very useful for studying the patterns in solar weather.

Helios probes

Main articles: Helios probes

The Helios probes were the next satellites to study the sun. Helios 1 made the closest approach to the Sun of any man-made object. The focus of these satellites was to study solar plasma, solar wind, and to study the magnetic and electrical field of the Sun.

Ulysses

Main articles: Ulysses (spacecraft)

Ulysses was the first spacecraft to study the north and south polar regions of the Sun. It was launched from the Space shuttle in October 1990. It carried instruments to study magnetic and electrical fields, and solar wind. The mission is still active today.

Solar and Heliospheric Observatory (SOHO)

Main articles: Solar and Heliospheric Observatory

SOHO was the largest and perhaps the most successful solar probe. It studied the chromosphere and corona of the Sun. It studied the interior of the Sun using helioseismology. During routine maintenance the satillite attitude control failed, and the satellite was almost lost.