ASTRON C12 Lecture 16: Lecture 16 – 3/16/17
Document Summary
Magnetic fields: common in nature, sun, space, many planets, recorded in rock. Magnetic fields in space: sun, earth and many other planets have internal magnetic fields, surround/protect planet, tell us about interiors, essentially the same as an electrical field. J = current density and changing e fields. Nothing goes faster than the speed of light. Funnel - can be a source of electric field. Electric field flow from positive to negative charge. Magnetic fields are the same as electric fields. How to make magnetic fields: rotation + convection (fluid moving around) + conductive fluid (liquid iron, plasma) = dynamo (magnetic fields) Solar dynamo: sun creates powerful internal magnetic field in convective region near surface, sun rotates more quickly at equator, stretching field lines and wrapping them up. Sunspots and activity: sunspots are related to magnetic activity, loops of gas originating from sunspots are unstable, causes chaos.
