1. Fluid Equations
Continuity Equation
Euler Equation
Energy Equation

2. Gravitational Acceleration
Gravitational Potential
Poisson Equation
Solution

3. Hydrostatics All time derivatives – zero Fluid velocity – zero
Heat Loss - zero

4. Solar Corona 1999 Total Eclipse Corona million times fainter than the
photosphere
Image: Luc Viatour

5. X-ray image
Yohkoh Soft X-ray Telescope (SXT).

6. Solar Corona Extremely tenuous and hot plasma At ~1.2 Solar radius
Temperature ~ 1.4 million Kelvin
Electron number density ~200 million/cc
Hotter than the surface of Sun (5800 K)

7. Heat Source Possibly small patches of magnetic field
Found across entire Sun
Possibly not the big Solar flares
Energy transfer through magnetic reconnections
Still an unresolved issue

8. Solar Wind Proposed by Parker 1958
Discovered ~1960, Soviet satellite Luna 1
Mainly electrons and protons
Near the Earth:
Number density 3 – 10 particles/cc
Flow Speed 400 km/s
Temperature 150,000 Kelvin

9. Solar Wind Occasionally streams 750 km/s
Occasional Impulse Events 1000 km/s
Solar wind can also have a measurable effects on the flight paths of spacecraft.

10. Heliosphere
100 AU
Image Source NASA/JPL/JHUAPL