  A non-negligible fraction of a Supermassive Black Hole's (SMBH) rest mass
energy gets transported into extragalactic space by a remarkable process in
jets which are incompletely understood. What are the physical processes which
transport this energy? It is likely that the energy flows electromagnetically,
rather than via a particle beam flux. The deduced electromagnetic fields may
produce particles of energy as high as $\sim 10^{20}$ eV. The energetics of
SMBH accretion disk models and the electromagnetic energy transfer imply that a
SMBH should generate a $10^{18} - 10^{19}$ Amp\`eres current close to the black
hole and its accretion disk. We describe the so far best observation-based
estimate of the magnitude of the current flow along the axis of the jet
extending from the nucleus of the active galaxy in 3C303. The current is
measured to be $I \sim 10^{18}$ Amp\`eres at $\sim 40$ kpc away from the AGN.
This indicates that organized current flow remains intact over multi-kpc
distances. The electric current $I$ transports electromagnetic power into free
space, $P = I^{2}Z$, where $Z \sim 30$ Ohms is related to the impedance of free
space, and this points to the existence of cosmic electric circuit. The
associated electric potential drop, $V=IZ$, is of the order of that required to
generate Ultra High Energy Cosmic Rays (UHECR). We describe the analogy of
electromagnetically dominated jets with transmission lines. High powered jets
{\it in vacuo} can be understood by approximate analogy with a waveguide. The
importance of inductance, impedance, and other laboratory electrical concepts
are discussed in this context. To appear in Proc. 18th International Symposium
on Very High Energy Cosmic Ray Interactions (ISVHECR2014), CERN, Switzerland

High Energy Astrophysical Phenomena