Plasma,Plasma,the 4the 4thth state of matter state of matterDone by :Jeremy Teo (14) 1O2

What is plasma?What is plasma?A plasma is a hot ionized gas

consisting of approximately equal numbers of positively charged ions and negatively charged electrons.

Characteristics of plasmaCharacteristics of plasmaPlasmas are made up of

electrically charged particles, strongly influenced by electric and magnetic fields.

Neutral gases are not.Plasmas are considered a distinct

"fourth state of matter."

Plasma and geomagnetic Plasma and geomagnetic fieldsfieldsPlasma is influenced

◦Externally - by the Earth's magnetic field or the interplanetary magnetic field and

◦Internally – by the localized charge concentrations and electric currents that result from the differential motion of the ions and electrons.

The forces affect the particles within the plasma. It gives the particles' behaviour a coherent, collective quality that neutral gases do not display.

The plasma universeThe plasma universeAbout 99% of the matter in the

observable universe is in the plasma state,

In our solar system, the Sun, the interplanetary medium, the magnetospheres and ionospheres of the Earth and other planets, as well as the ionospheres of comets and certain planetary moons all consist of plasmas.

Space plasmasSpace plasmasThe plasmas of interest to space

physicists are extremely tenuous, with densities dramatically lower than those achieved in laboratory vacuums.

The temperatures of space plasmas are very high, ranging from several thousand degrees Celsius in the plasma sphere to several million degrees in the ring current.

While the temperatures of the "cooler" plasmas of the ionosphere and plasma sphere are typically given in degrees Kelvin, those of the "hotter" magnetospheric plasmas are more commonly expressed in terms of the average kinetic energies of their constituent particles measured in "electron volts."

An electron volt (eV) is the energy that an electron acquires as it is accelerated through a potential difference of one volt and is equivalent to 11,600 degrees Kelvin.

Magnetospheric plasmas are often characterized as being "cold" or "hot." Although these labels are quite subjective, they are widely used in the space physics literature.

As a rule of thumb, plasmas with temperatures less than about 100 eV are "cold," while those with temperatures ranging from 100 eV to 30 keV can be considered "hot." (Particles with higher energies--such as those that populate the radiation belt--are termed "energetic.")

Examples of artificially Examples of artificially produced plasmas produced plasmas Those found in plasma displays,

including TVsInside fluorescent lamps (low

energy lighting), neon signsRocket exhaust and ion thrustersThe area in front of

a spacecraft's heat shield during re-entry into the atmosphere

Inside a corona discharge ozone generator

Plasma ball or plasma globeArcs produced by Tesla coils (resonant

air core transformer or disruptor coil that produces arcs similar to lightning but with alternating current rather than static electricity)

Plasmas used in semiconductor device fabrication including reactive-ion etching, sputtering, surface cleaning and plasma-enhanced chemical vapor deposition

Laser-produced plasmas (LPP), found when high power lasers interact with materials.

Fusion energy researchThe electric arc in an arc lamp, an

arc welder or plasma torchInductively coupled plasmas (ICP),

formed typically in argon gas for optical emission spectroscopy or mass spectrometry

Magnetically induced plasmas (MIP), typically produced using microwaves as a resonant coupling method

Examples of terrestrial Examples of terrestrial plasmas plasmas LightningBall lightningSt. Elmo's fireUpper-atmospheric lightningThe ionosphereThe polar auroraeMost flames

Examples of space and Examples of space and astrophysical plasmasastrophysical plasmasThe Sun and other stars

(plasmas heated by nuclear fusion)

The solar windThe interplanetary medium

(space between planets)The interstellar medium

(space between star systems)

The Intergalactic medium(space between galaxies)

The Io-Jupiter flux tubeAccretion discsInterstellar nebulae

ReferencesReferenceshttp://pluto.space.swri.edu/IMAG

E/glossary/plasma.htmlhttp://www.google.com.sg/http://www.google.com.sg/imghp

?hl=en&tab=wihttp://en.wikipedia.org/wiki/Plasm

a_(physics)

Thank you for all your Thank you for all your attention!attention!