Revision as of 16:15, 18 October 2009 by Walden
- Plasma (Classical element: Fire)
- (to correct: since the mainstream atomic model concept used here isn't correct) "A plasma is typically an ionized gas. Plasma is considered to be a distinct state of matter because of its unique properties. Ionized refers to presence of one or more free electrons, which are not bound to an atom or molecule. The free electric charges make the plasma electrically conductive, meaning that it responds strongly to electromagnetic fields."
- Plasmas are by far the most common phase of matter in the universe, both by mass and by volume. It is often stated that more than 99% of the universe is plasma.
- There are 3 distinctly different steady state modes in which a plasma can operate :
- Dark Current Mode - The strength of the electrical current (flow of charged particles) within the plasma is very low. The plasma does not glow. It is essentially invisible. We would not know a plasma was there at all unless we measured its electrical activity with sensitive instruments. The present day magnetospheres of the planets are examples of plasmas operating in the dark current mode.
- Normal Glow Mode - The strength of the electrical current (flow of charged particles) is significant. The entire plasma glows. The brightness of the glow depends on the intensity of the current in the plasma. Examples: Any neon sign. Emission nebulae. The Sun's corona.
- Arc Mode - The strength of the electrical current in the plasma is very high. The plasma radiates brilliantly over a wide spectrum. Current tends to form twisting filaments. Examples of this mode of operation are: An electric arc welding machine. Lightning. The Sun's photosphere.
- Birkeland currents:
- "Electric current, passing through a plasma, will take on the corkscrew (spiral) shape discovered by Birkeland. These Birkeland currents most often occur in pairs. There is a tendency for these pairs to compress between them any material (ionized or not) in the plasma. This is called the "Z-pinch" effect. The ability of Birkeland currents to accrete and compress even non-ionized material is called "Marklund convection"." 
- "A Birkeland current generally refers to any electric current in a space plasma, but more specifically when charged particles in the current follow magnetic field lines (hence, Birkeland currents are also known as field-aligned currents). They are caused by the movement of a plasma perpendicular to a magnetic field. Birkeland currents often show filamentary, or twisted "rope-like" magnetic structure." The reason for this twisting is that at a longer distance the magnetic field currents are attracted to each other, but at a shorter distance they repel each other.
- See also:
- "plasma-universe.com: Plasma"
- "Introduction to Plasma Physics: A graduate course"
- Plasma physics (Category:Plasma physics)
- Waves in plasmas (articles from Wikipedia)
- Plasmametaphysics.com (web site on the life-like properties of plasma fields - aka "plasma life")
Plasma density comparison diagram