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