Table 1
Typical ionospheric parameters (Boyd & Raitt 1965) at two altitudes

Parameter	Symbol	Unit	@ 400 km	@ 800 km
Magnetic field	B	gauss	0.5	0.4
Neutral Ptl. density	no	cm-3	2×108	2×106
Positive ion density	n+	cm-3	106	105
Electron density	ne	cm-3	106	105
Neutral temperature	Tn	K	1,400	1,400
Electron temperature	Te	K	2,800	3,000
Average ion mass	M+	a.m.u.	20	14
Electron debye length	λD	cm	0.4	1
Neutral Ptl mean-free-path	λo	cm	2×106	2×108
Electron-Ion mean-free-path	λe+	cm	1×105	1×106
Electron-Neutral Ptl. collision freq.	νeo	sec-1	2.5	2×10-2
Electron-Ion collision freq.	νe+	sec-1	3×102	3×101
larmor radius of + ion	ρ+	cm	5×102	7×102
Larmor radius of electron	ρe	cm	3	4