1. Magnetic Field

2. Creating a Field
When very hot, atoms lose their negatively charged electrons and become positively charged ions.
The flow of these charges creates a magnetic field.
Magnetic fields form imaginary lines of magnetic force.
moving charges
magnetic field lines

3. Magnetic Structures
Magnetic field lines in the chromosphere create arcs.
Prominences in arcs
Magnetic field lines shape the corona.
Peak as solar flares

4. Magnetogram
The HMI on the Solar Dynamics Observatory can measure magnetic fields on the Sun.
Detailed study of active regions

5. Sunspots
Magnetic regions stronger than normal exist in the photosphere.
Sunspots are dark and much cooler regions.
3700 K compared to 5800 K
Sunspots typically last for days.
Watching their motion helped determine the sun’s rotation (25 days).

6. Sunspot Cycle Sunspots increase and decrease in an 11 year cycle.
Rotating Sun and warping magnetic fields
Fields break down and restart
The position on the sun also varies over the cycle.

7. Space Weather Peak sunspot activity is associated with solar flares.
Increased solar wind and auroras
Disrupted communications
Earth’s climate warms when the Sun is more active.
1/3 to 1/2 recent changes