ASTRON 1F03 Lecture Notes - Lecture 17: Photosphere, Chromosphere, Pauli Exclusion Principle
18 Dec 2015
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Document Summary
Sunspots are colder places where magnetic fields stop convection. **stefan"s law: the cold sunspot (4000k) emits a lot less than the typical photosphere (6000k). The sun has a very strong magnetic field. Solar dynamo: strong convection and rotation produce the same magnetic field, this is not a static situation the magnetic field is continually changed. When the solar magnetic field is strong, it pushes out of the solar surface: sunspots. Sunspots only occur when the field is strong. Field reverses and weakens again every 11 years. Sun shows an 11-year sunspot cycle (part of 22-year magnetic cycle). The maunder minimum showed a distinct lack of sunspots between 1645 and 1715. Prominence: hot rising gas in the chromosphere constrained by magnetic fields. Solar flares and coronal mass ejections are highly energetic, violent bursts and eruptions. Solar storms can disrupt electric power grids and satellites. Without a source of new energy, they tend to contract and become fainter (e. g. giant.
