  A new representation of electromagnetic gyrokinetic Vlasov-Maxwell theory is
presented in which the gyrocenter equations of motion are expressed solely in
terms of the perturbed electric and magnetic fields. In this representation,
the gyrocenter symplectic (Poisson-bracket) structure and the gyrocenter
Jacobian contain electric and magnetic perturbation terms associated with the
standard first-order gyrocenter polarization and magnetization terms that
traditionally appear in the gyrokinetic Maxwell equations. In addition, the
gyrocenter polarization drift (which includes perturbed magnetic-field
corrections) now appears explicitly in the gyrocenter velocity. The symplectic
gyrokinetic Vlasov-Maxwell equations are self-consistently derived from a
constrained Eulerian variational principle, which yields exact energy-momentum
conservation laws (through the Noether method) that are verified explicitly. An
exact toroidal canonical angular momentum conservation law is also derived
explicitly under the assumption of an axisymmetric background magnetic field.
