Lesson5

goodyearmiaowΜηχανική

18 Νοε 2013 (πριν από 3 χρόνια και 11 μήνες)

86 εμφανίσεις

Part I

Object of Plasma Physics

BACK

1. Characterization of the Plasma State

2. Plasmas in Nature

3. Plasmas in the Laboratory

I. Object of Plasma Physics

Natural and Laboratory Plasmas



Typical Values for the Debye Length


Typical values of Debye Length under different
conditions:





n [m
-
3
] T[eV] Debye Length [m]


Interstellar


10
6



10
-
1



1

Solar Wind


10
7



10


10

Solar Corona

10
12



10
2



10
-
1


Solar atmosphere

10
20



1


10
-
6


Magnetosphere

10
7



10
3



10
2


Ionosphere


10
12



10
-
1



10
-
3


Interstellar Plasma Exploration




Interstellar Plasma Exploration




Interstellar Plasma Mission Objectives


Measure the interstellar magnetic field and the density,
temperature, and ionization state of the interstellar
gas




Determine the interstellar spectra of galactic cosmic
rays and their contribution to the ionization, heating,
and dynamics of the interstellar medium.


Determine the mass and velocity distributions and the
composition of interstellar dust


Measure the elemental and isotopic composition of
interstellar plasma, neutral gas




Measure cosmic ray electrons and positrons and study
their implications for galactic gamma ray production,
recent nucleosynthesis, and interstellar radio emission



The Plasma in the Stars

The Sun: a very old fusion reactor

The Sun
-
Earth Connection

The solar wind is a stream of charged nuclei (H, He)
constantly emitted from the Sun

Earth Magnetosphere

Dipolar Earth magnetic field

Earth Ionosphere

Ionospheric plasma interactions

Earth Ionosphere (II)

The Sun

Detectors on ISS

Galactic Cosmic Rays

Earth Magnetosphere

Ionospheric plasma interactions

1. Characterization of the Plasma State

2. Plasmas in Nature

3. Plasmas in the Laboratory

I. Object of Plasma Physics

The Deuterium Tritium Reaction

Fusion Experiments

The First Tokamak (Moscow, Russia)

The DIII
-
D Tokamak (San Diego, CA, USA)

The DIII
-
D Tokamak (San Diego, CA, USA)

The DIII
-
D Tokamak (San Diego, CA, USA)

The Jet Tokamak (U.K.)

The Jet Tokamak (U.K.)

The Jet Tokamak (U.K.)

Inside the torus:

the Mascot Remote
Handling
Manipulator on the
end of the boom,
during the Remote
Tile Exchange phase


The Z
-
Pinch Concept

The ZaP Z
-
Pinch Experiment (Seattle, WA)

The MIT Levitated Dipole eXperiment (Boston, MA)

The MIT Levitated Dipole eXperiment (Boston, MA)

The MIT Levitated Dipole eXperiment (Boston, MA)

The Field Reversed Configuration (Seattle, WA)

Imploding FRC Experiment (Los Alamos, NM)

The Stellarator (Garching, Germany)

The Stellarator

Simulated Stellarator confined plasma surface

The Helically Symmetric eXperiment (Madison, WI)

Industrial Plasmas

Industrial Plasmas (II)

Industrial Plasmas
-

Consumer


High
-
efficiency lighting


Manufacturing of semiconductors “chips” (wafer
etching)


Flat
-
panel displays


Surface treatment of synthetic cloth for dye adhesion


Fluorescent Lamp


A

fluorescent lamp is shown here with part of the phosphor
coating removed to reveal the blue plasma glow inside. The
phosphor is the white coating on the lamp wall.


The plasma excites lamp's phosphor coating to produce the
visible light

Arc Lamps


In high
-
intensity arc lamps the light is generally
produced directly by the plasma.


Color characteristics are controlled by the chemical
elements put into the plasma rather than by a phosphor
coating on the wall.

Plasma displays


Plasma displays generally consist of two glass plates,
each containing parallel electrodes, sealed to form an
envelope filled with a neon and xenon gas mixture.


A gas discharge plasma is created by applying an
electric field between the electrodes.


Plasma displays (II)


The plasma generates ultraviolet light which in turn
excites the phosphor coating inside the glass envelope.



The phosphor emits a single color of visible light.



Each pixel consists of three sub
-
pixels, one each of
red, green and blue.


By combining these primary colors at varying
intensities, all colors can be formed.

Isotope Separation


Plasma sources and magnetic field control of gyrating
charged plasma particles can be used for the separation
of stable isotopes for medical and industrial use.

Plasmas for Sterilization


One
-
atmosphere plasma systems are now becoming
available for various industrial applications.


One
-
atmosphere plasma systems make possible new
methods for surface cleaning (sterilization for food,
medical, and other applications)


Heat sterilization is time consuming and irradiation
can damage materials: this new plasma technology has
been shown to kill bacteria on various surfaces in
seconds to minutes.


In addition to destroying bacteria, such plasma systems
also destroy viruses, fungi and spores.


These systems also provide an environmentally benign
method for pre
-
treating surfaces.

Aerospace Technology


Modification of Aerodynamic Drag: flat panel with a
layer of one
-
atmosphere plasma undergoing wind
tunnel testing. (Univ. of Tennessee)

Aerospace Technology


Microwave generated plasma around a catalyst for
removal of NOx and CO from engine exhausts


Aerospace Technology


Test of electrostatic ion thruster in large vacuum
chamber

Aerospace Technology


Robotically controlled plasma spraying of high
-
temperature shielding tiles