Derived Parameter: Proton-Proton Collision Frequency

Proton-Proton Collision Frequency

The proton-proton collision frequency given here is for the thermal case where two Maxwellians are at nearly equal temperatures interact.

$\nu _{pp}= 6.01\times 10^{-2}\frac{n_p \lambda_{pp}}{T^{1.5}} \ \ \mathrm{Hz}$

where n_p is proton density in cm^-3, T is in Kelvins, and

$\lambda_{pp} = 8.96-\ln \left ( \frac {2 \sqrt{n_p}}{T^{1.5}} \right )$

Proton collision frequency values for quiet Sun (Model 1001; blue), facula (1005; red), and umbra (1006; green).

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