Fundamentals of Plasma Physics

Appendix C

Frequently used physical constants and

formulae

Physical constants (to 3 significant figures)
symbol value unit
electron mass me 9. 11 × 10 −^31 kg
proton mass mp 1. 67 × 10 −^27 kg
vacuum permeability μ 0 4 π× 10 −^7 N A−^2
vacuum permittivity ε 0 8. 85 × 10 −^12 F m−^1
speed of light c 3. 00 × 108 m s−^1
electron charge e 1. 60 × 10 −^19 C
Avogadro’s number 6. 02 × 1023 mol−^1
Boltzmann constant κ 1. 60 × 10 −^19 J eV−^1

Formulae

(all quantities in SI units, temperatures in eV,Ais ion atomic mass number)

Lengths

Debye length (p.7)

1

λ^2 D

=

∑

σ

1

λ^2 σ

whereσis over all species participating in shielding and

λσ=

√

ε 0 κTσ

n 0 σqσ^2

=7. 4 × 103

√

Tσ

n (^0) σ
m
Electron Larmor radius (p.234)
rLe=

√

κTe/me

|ωce|

=2. 4 × 10 −^6

√

Te

B

m

Ion Larmor radius (p.234)

rLi=

√

κTi/mi

|ωci|

=1. 0 × 10 −^4

√

ATi

B

√

Z

m

whereAis atomic mass andZis ion charge.
Electron collisionless skin depth (p.145)

c

ωpe

=

5. 3 × 106

√

ne

m

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