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Plasma

Plasma. Electrons are free! … A fourth state of matter: Not gas, not liquid, not solid!. History, Terminology, & Discovery. First identified by Sir William Crookes (1879) Termed by Irving Langmuir Ionosphere identified as plasma Van Allen Belts (1958). Types of Plasma.

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Plasma

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  1. Plasma Electrons are free! … A fourth state of matter: Not gas, not liquid, not solid!

  2. History, Terminology, & Discovery • First identified by Sir William Crookes (1879) • Termed by Irving Langmuir • Ionosphere identified as plasma • Van Allen Belts (1958)

  3. Types of Plasma Artificially Induced Terrestrial & Astrophysical Stars (Sun) Ionosphere Aurora Borealis Lightning Most fires TLE • Fluorescent lamps • Neon Signs • Plasma televisions • Electric arcs (i.e. those created by a Marx generator,etc.) • Laser-Produced Plasmas (LPP) • Rocket exhaust • Ion Thrusters

  4. Plasma: A Fourth State of Matter • Ionized “gas” • Most are quasi-neutral • Said: ~99% of matter • Affected by E&M waves • Characteristics • Electron density: • Temperature: • Molecular Content • Electron Plasma Frequency: • Debye Length:

  5. Plasma Physics • Maxwell’s Equations: Statistics, Mathematics, the Most General Case • Maxwell-Boltzmann Distribution: particle density distribution • Fluid Mechanics: Three particle, nonviscous intermingled fluids coupled through their equations of state and collision frequencies

  6. Wave Propagation • Propagation constant: • Approaches free space • value: • Turns imaginary • Wave propagation highly dependent on electron plasma frequency: • If then the wave propagates through • If then the wave is deflected • Deflection Case: • Fields vary exponentially • Phase-variation terms decay exponentially (the wave will • decay as it propagates) • e.g. Ionosphere reflects E&M radiation with frequency less • than its plasma frequency

  7. Example: If lightning were to propagate toward the ionosphere would it be deflected? Why or Why not? • Ionosphere: • Lightning: Answer: It will not be deflected as its frequency is larger than that of the ionosphere

  8. References • 1909, who valued professional, financial success as well as scientific inquiry, accomplishment, his summer position stretched into a lifelong career. He became known among his colleagues for his analytical mind, creativity, ambition, and excellent research skills.. "Irving Langmuir." Ziggo. N.p., n.d. Web. 1 July 2010. http://members.home.nl/arjen.boogaard/Irving%20Langmuir.html. • "Brief History of Plasma Physics." Home Page for Richard Fitzpatrick . N.p., n.d. Web. 1 July 2010.http://farside.ph.utexas.edu/teaching/plasma/lectures/node5.html. • "Fields & Waves I v2." Plasma Dynamics Lab. N.p., n.d. Web. 1 July 2010. http://hibp.ecse.rpi.edu/~connnor/education/Fields/F09/. • "Plasma (physics)." 2008/9 Wikipedia Selection for schools. N.p., n.d. Web. 1 July 2010. http://schools-wikipedia.org/wp/p/Plasma_%2528physics%2529.htm. • "Plasma Physics -- History." NASA Polar, Wind, and Geotail Projects. N.p., n.d. Web. 16 June 2010. http://www-spof.gsfc.nasa.gov/Education/whplasma.html. • "Plasma Physics." National Ignition Facility & Photon Science. N.p., n.d. Web. 1 July 2010.https://lasers.llnl.gov/programs/science_at_the_extremes/plasma_physics/. • Riegel, ron. "Irving Langmuir - Wikipedia, the free encyclopedia." Wikipedia, the free encyclopedia. N.p., n.d. Web. 28 June 2010.http://en.wikipedia.org/wiki/Irving_Langmuir. • Uman, Martin A. Introduction to Plasma Physics. New York: McGraw-Hill, 1964. Print.

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