Electrodynamics
Most natural and manmade aerosols carry charges, and their behavior is strongly affected by their charge. In this section the consequences of charges on dynamic of aerosols are discussed. A brief review of electrodynamics is first presented. The Maxell equations governing electrodynamics are listed in Table 1.
Table 1. Electrodynamics equations.
Maxwell’s Equations |
Gaussian Units |
MKS Units |
Coulomb’s Law |
![](images/image001.gif)
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![](images/image002.gif)
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Ampere’s Law |
![](images/image003.gif)
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![](images/image004.gif)
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Faraday’s Law |
![](images/image005.gif)
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![](images/image006.gif)
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Absence of Free Magnetic Poles |
![](images/image007.gif)
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![](images/image007.gif)
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Continuity Equation |
![](images/image008.gif)
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Constitutive equations for free space are given as:
Ohm’s Law is given by
In these equations:
D = Electric Displacement c = Speed of Light
B = Magnetic Induction = Dielectric Constant
E = Electric Field = Permeability
H = Magnetic Field = Conductivity
J = Current = Charge Density
Note that 1 electronic unit of charge = Statcoulombs =
Coulombs (MKS). A conversion table for different physical quantities are given in Table 2.
Table 2. Conversion Table
Physical Quantities |
Symbol |
MKS |
Gaussian |
Length |
![](images/image023.gif)
|
1 meter (m) |
102 centimeter (cm) |
Mass |
m |
1 kilogram (kg) |
103 gram (gm) |
Time |
t |
1 second (s) |
1 second (s) |
Force |
F |
1 newton (N) |
105 dynes |
Work, Energy |
W, U |
1 joule (J) |
107 ergs |
Power |
P |
1 watt (W) |
107 ergs/s |
Charge |
q |
1 coulomb (coul) |
statcoulomb
|
Charge Density |
![](images/image025.gif)
|
1 coul/m3 |
statcoul/cm3
|
Current |
I |
1 ampere (coul/s) |
statampere
|
Current Density |
J |
1 amp/m2 |
statamp/cm2
|
Electric Field |
E |
1 volt/m |
statvolt/cm
|
Electric Potential |
V |
1 volt |
statvolt
|
Polarization |
P |
1 coul/m2 |
dipole moment/cm3
|
Displacement |
D |
1 coul/m2 |
statcoul/cm2 (statvolt/cm)
|
Conductivity |
![](images/image019.gif)
|
1 mho/m |
1/s
|
Resistance |
R |
1 ohm |
s/cm
|
Capacitance |
C |
1 farad |
cm
|
Magnetic flux |
F |
1 weber |
gauss cm2 (maxwell)
|
Magnetic induction |
B |
1 weber/m2 |
gauss
|
Magnetic field |
H |
1 amp-turn/m |
oersted
|
Magnetic Induction |
M |
1 amp/m |
magnetic moment/ cm3
|
Inductance |
L |
1 henry |
![](images/image032.gif)
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For accurate works, all factors of 3 in the coefficients should be replaced by 2.99793. |
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