| 摘要 |
A novel device and method are provided herein for the production of underwater sound. This device, termed a plasma jet underwater acoustic source includes a central electrode and a concentric insulator having a longitudinal bore to accommodate the central electrode, the bore being spaced from the central electrode by a longitudinally-extending annular chamber. A plasma cavity is bounded at its upper end by the central electrode, and is in communication with the annular chamber. The cavity is adapted to be connected to a gas supply, so that it may be filled with gas. An outer housing of electrically-conductive material surrounds the insulator and terminates in a centrally-apertured end plate whose central aperture provides an extension to the plasma cavity, the end plate being adapted to be grounded. Connectors are provided for connecting the central electrode first to a source of low energy and high voltage to create an electrical discharge across the gas within the plasma cavity and then to a source of stored electrical energy of comparatively low voltage, e.g. in the range of hundreds of volts. An electrical discharge between the inner conductor and the grounded annular end plate thus causes the gas in the cavity to heat rapidly. The resulting overpressure expels the gas initially at supersonic speeds into the water. The ejected gas from the cavity forms a compression zone, a bubble, and a plasma plume, the compression zone producing the acoustic pulse.
|
