McIlwain L Parameter for Fermi (gdt.missions.fermi.mcilwainl)

The function calc_mcilwain_l() is used to estimate the McIlwain L parameter, which describes a subset of the geomagnetic field lines and is correlated with trapped charged particle density.

This is a specialized function for Fermi, assuming Fermi’s approximate altitude, and which implements a cubic polynomial approximation to the full calculation of the McIlwain L parameter as a function of latitude/longitude. It is only valid within the East latitude range of \((-30^\circ, +30^\circ)\), which covers the extent of Fermi’s orbit.

As an example, we can calculate the McIlwain L parameter if Fermi were at \(20^\circ N, 100^\circ W\) (over Central America, just outside of Mexico City):

>>> from gdt.missions.fermi.mcilwainl import *
>>> # note that we must specify East Longitude
>>> calc_mcilwain_l(20.0, -100.0)
1.44546112

Reference/API

gdt.missions.fermi.mcilwainl Module

Functions

calc_mcilwain_l(latitude, longitude)

Estimate the McIlwain L value given the latitude (-30, +30) and East Longitude.