2.3 Summary of the phase-space coordinate transform

The coordinate transform from particle coordinates (x,v) to guiding-center coordinates (X,𝜀,μ,α,σ) is given by

(                 e∥(x)
|||| X(x,v) = x+2 v × Ω(x)
||{ 𝜀(x,v ) = |v|2-+ qΦ0m(x)
  μ(x,v) = |v−v⋅e∥(x)|2
||||           2B0(x)
||( α(x,v) = (angle between v⊥ and locale⊥)
  σ(x,v) = sign(v ⋅e∥(x))
(14)

As mentioned above, the dependence of the distribution function on σ will not be explicitly indicated in the following.