In the charge-starved limit, a vacuum gap will spread outward from the flow division surface if there is no substantive pair injection mechanism as is quite possibly the case in M87. In this charge starved limit, the surrounding magnetosphere is a semi-vacuum. The only significant source of electromagnetic fields is within the flux tube. The very tenuous stray charges have trajectories that are affected by these fields, but the number density is too small to provide a source for a significant perturbation to these fields. Charges can only flow inward across the charge horizon (Komissarov 2004; Punsly 2004).