Formation and ejection of double-helix plasma structures from gravitational waves emitters.

Double-helix plasma structures have been identified theoretically and shown to form in and propagate away from the time-dependent plasmas in which black-hole binaries can be imbedded. These structures are envisioned to propagate up to plasma regions where they can be disrupted. By now experimental observations of the termination of jets have revealed that they can involve double-helix magnetic topologies. Theoretically these structures are found to emerge as non-linearly coupled torsional Alfvén waves in the presence of a magnetic field in both the formation and in the terminal plasma while evolving into torsional ion sound waves when the background magnetic field vanishes. They corotate with the binary and propagate in either of the two vertical directions. The coupling involves intrinsic gravitational modes present in the circumbinary disk and inner gravitational fluctuations originating from the swept (toroidal) regions traced by one or both black holes.