RESUMO
Recent experiments have shown that femtosecond filamentation plasmas generate ultrabroadband radio frequency radiation (RF). We show that a combination of plasma dynamics is responsible for the RF: A plasma wake field develops behind the laser pulse, and this wake excites (and copropagates with) a surface wave on the plasma column. The surface wave proceeds to detach from the end of the plasma and propagates forward as the RF pulse. We have developed a four-stage model of these plasma wake surface waves and find that it accurately predicts the RF from a wide range of experiments, including both 800-nm and 3.9-µm laser systems.
RESUMO
The extraction of rotational energy from a spinning black hole via the Blandford-Znajek mechanism has long been understood as an important component in models to explain energetic jets from compact astrophysical sources. Here we show more generally that the kinetic energy of the black hole, both rotational and translational, can be tapped, thereby producing even more luminous jets powered by the interaction of the black hole with its surrounding plasma. We study the resulting Poynting jet that arises from single boosted black holes and binary black hole systems. In the latter case, we find that increasing the orbital angular momenta of the system and/or the spins of the individual black holes results in an enhanced Poynting flux.
