Particles, Grids and Units

Particles

Below is a table of the currently implemented particles (i.e. their particle properties are defined within the code)

Particle	Abr. String	Mass (units of $m_{\text{Ele}}$)	Charge (units of $q$ the fundamental charge)
Sphere	"Sph"	1836.1528 (mass of Proton)	0.0
Electron	"Ele"	1.0	-1.0
Positron	"Pos"	1.0	1.0
Proton	"Pro"	1836.1528	1.0
Photon	"Pho"	0.0	0.0

Grids

Three types of grids for coordinates in phase space have been implemented

Grid Spacing	Abr. String	Notes
Uniform	"u"	Uniform grid spacing between the upper and lower bounds
Log10	"l"	Exponentially increasing grid spacing, uniform in Log10 space from upper to lower bounds (bounds should be given as Log10(bound value))
Binary	"b"	Fractionally decreasing grid spacing for angular grids. Bin widths half as they move away from u=0 in both directions to u=+-1.

Units

Within Diplodocus, the speed of light $c$ is taken to be unity and all masses, momenta and energies are normalised by the rest mass of the electron $m_{\text{Ele}}$. Further all interaction rates are normalised by ${\sigma }_{\text{T}}c$, where ${\sigma }_{\text{T}}$ is the Thompson scattering cross section. Therefore time $t$ is given by $t[s]=t[\text{code units}]/{\sigma }_{\text{T}}c\approx 5\times {10}^{19}[s]\ast t[\text{code units}]$, with $t[codeunits]$ corresponding to the characteristic time for an interaction with cross section ${\sigma }_{\text{T}}$ and particle density $1[m^{-3}]$.