Intense laser pulse driving blowout cavity in plasma — GV/m accelerating fields
In the blowout (bubble) regime (a₀ > 1), the laser ponderomotive force expels all electrons radially, creating a spherical ion cavity trailing the pulse. Fields reach E ~ E₀√(n/n_c) ≈ GV/m. Dephasing length L_d ~ (n_c/n)^(3/2) λ_p limits energy gain; GeV electrons are achieved in cm-scale plasmas at FACET, BELLA, and EuPRAXIA.