Solar Atmospheres

Topics

• Chromosphere

• Corona

• Solar Wind

• Solar Magnetism

• Transition Zone and the Corona

Chromosphere

• ->emits very little light of its own. Can not be seen directly it is pinkish blue due to H alpha emission lines. Can be seen at eclipses

• -> spicules- solar storms emitted leave atmosphere around 100km/h and hit high above the photosphere. Near the edges of super granules Why? Magnetic field constructive interference

Corona and transition zone

• Corona- also seen only on eclipses when the moons angular size blocks the photosphere

• spectra changes from absorption to emission• upper chromospheres temps are way hotter than

photosphere• corona is still hotter• transition zone yields high temps, why is not

clear.

Solar Wind

• escaping solar particles (protons and electrons) @500km/ hr

• what’s happening? *query, sun is constantly evaporating and losing mass-

• the high temps replenish the sun from below

• about 1million tons shed per second, less than .1 % since formation of the sun

Solar Magnetism

• sun spots have a magnetic profile 1000X greater than surrounding area

• flows from s- n pole of spot, Polarity reversed on southern hemisphere

• occur in pairs with opposite polarities.• Light emitted by charged particles• Solar magnetic field warped by equator

(differentially rotates) and eventually wraps it and the result is a prominence

Solar Cycle

• temporary and unstable and there is an 11 year cycle of activity

• Sun spots start closer to poles and then work way towards equator

• Polarities reverse once they cross the equator

• Not constant can vary from 7-15 years

Corona and the Solar Cycle

• corona heated by solar surface activity

• this injects large amounts of energy into the atmosphere

• fueled by small scale magnetic loops

• linked in time to the solar cycle