Plasma - What It Is, What It isn’t A Shocking Exposé with Investigations by McGourty and Rideout

4 th State of Matter Superheated gas Has absorbed enough energy to allow electrons to break free from atoms (free electrons) Made up of free electrons and positive ions Most abundant state of matter in the universe You can find out more by visiting this cool websitecool website

4 States of Matter - This Shouldn’t Even Phase You

Where Do We Find Plasma?Plasma The Sun Other Stars The Ionosphere Lightning Neon Lights

Properties of Plasmas Remain electrically charged Carry electric currents Produce both electric and magnetic fields Produce electromagnetic radiation Has a characteristic frequency called the “plasma frequency”

Plasma Frequency Since plasma has both positive and negative charges, they are constantly oscillating back and forth. This results in a characteristic frequency called the Plasma Frequency The plasma frequency is a resonant frequency of the ionized gas - it depends on the square root of the electron density + -

Plasma and the Ionosphere Radio waves can only penetrate the ionosphere if the frequency of the wave is higher than the plasma frequency; otherwise the signal is reflected back We have to use high frequencies to communicate with satellites. Frequencies lower than the plasma frequency have to be used to communicate with a radio station beyond the horizon so that the signal will be reflected back to Earth

Why Do We Care About Plasma?

Faraday Rotation As a wave moves through a plasma, the polarization plane can rotate because of the influence of the magnetic field. This effect is known as Faraday rotation Strength of magnetic fields can be measured using knowledge of rotation and electron density Pulsars, heliospheric information - look at known source and changes in polarization due to FR to create models

The solar wind causes energy changes in the incoming wavefront