Density and payload potential
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Transcript of Density and payload potential
Density and payload potential
HM, Erpa, PFISR, waves
Density from HF?
First try inconsistent
Consider rammed thermal ions
But analysis assumes O+ only
How about the e- erpa? Its skin channel is a langmuir probe with V_b=+4VBut it doesn’t know about phi-s/c; also, no absolute scale
Certainly a density “hole” where precip is; but should there be?
PFISR
Velocity fields as aurora alarm
VLOS
Density
Density profiles
Density from LHR?
Gives few-15*10^3/cc if O+
What if NO+?
ERPA stuff
• Electron RPA with +4V front screen• Skin channel = LP @4V• Erpa-peak => energy of peak response• Erpa-hi = electrons greater than 3eV (non-
thermal)• Temp: phi_sc = 5kT+Vsphere-skin• (sphere float plus differential charging to skin)
Comparisons of phi-sc
Dots: HM peak –Eram
Black lines: 5kTe + avg(Vss) sub and fwd, no tweaks
Blue lines: aft-erpa-peak fwd-erpa-peak – 0.42
HM cutoff ~1eV
ERPA cutoff ~0.8eV
Truest: 5kTe+avg(Vss)
Correcting erpa-peak
Upper black: truest
Bottom black: aftpeak
Blue:Aftpeak + afthi*200
True from Te and HM consistent
Erpapeaks have payload- dependent DC offset
Erpapeaks suppressed by higher energy e- flux
Another payload, dayside cusp