Struct

`space::irbem::T89Parameters`

cheatah-space v0.1.0-alpha — Biome Standard 0.6.5-alpha

One Kp bin's fitted parameters — Tsyganenko (1989) Table 1, one column.

Templated on the scalar type for one reason and it is not generality: the device kernel receives these as float, so the host lane that the kernel is verified against must round them to float FIRST and then evaluate, or the two lanes are not running the same arithmetic and a disagreement cannot be attributed. t89_parameters is the converter, and the fp64 and fp32 instantiations are the only two that exist.

Template parameters

`T`	the scalar type; `double` for the reference lane, `float` for the device-mirroring one.

Unit testIrbemT89.PublishedCoefficientsAreDivergenceFree

Constants & variables

var std::array< T, t89_linear_count > c #

The nineteen linear coefficients, zero-based: element k is the paper's C(k+1), so element zero is C_1.

C_1 and C_2 weight the two tail potentials; C_3 and C_4 the symmetric and tilt-antisymmetric closure currents; C_5 the ring current; the remaining fourteen are the eq. (20) expansion. Units are whatever makes the field come out in nT with positions in Earth radii, which is the paper's convention throughout.

var T delta_x #

dx, R_E — the e-folding length of eq. (20)'s radial envelope.

var T a_rc #

a_RC, R_E — the ring current's radial scale length; the radius of its density maximum.

var T d_0 #

D_0, R_E — the current sheet half-thickness in the central magnetotail.

var T gamma_rc #

gamma_RC, R_E — the ring-current sheet's dayside-to-nightside thickness increment.

var T r_c #

R_c, R_E — the "hinging distance": how far out the sheet leaves the dipole equator.

var T g #

G, R_E — the amplitude of the sheet's transverse (dawn-dusk) bending.

var T a_t #

a_T, R_E — the tail current's radial scale length.

var T d_y #

D_y, R_E — the dawn-dusk scale over which the truncation factor W falls off.

var T x_0 #

x_0, R_E — where along the Sun-Earth line W makes its transition.