Presentation Title

Solutions to the radio blackout effect of plasma sheaths at hypersonic and reentry velocities

Start Date

November 2016

End Date

November 2016

Location

Surge 172

Type of Presentation

Oral Talk

Abstract

Airborne vehicles traveling through an atmosphere at hypersonic velocities, especially in excess of Mach 15, face significant atmospheric heating that produces a plasma sheath which surrounds the vehicle, making communication to and from the hypersonic vehicle difficult or impossible. Various methods of communicating through the plasma sheath have been proposed and studied since the early 1960’s, yet a single elegant solution has not been found in unclassified research to date. These solutions can be divided into two basic types: passive methods, which minimize blackout conditions through the vehicle or mission design, and active methods, which use active systems to change or exploit the properties of the plasma flow field to communicate through the plasma barrier. Two active methods are presented as particularly likely to provide a solution which minimizes impact on vehicle performance and design while remaining effective. In the first, E × B Lorentz forces are used to create "windows" in the plasma through which radio communication is possible. Initial laboratory and simulation results indicate this technique could present a good solution. A second method that has been theoretically studied to date uses Raman interactions of an electromagnetic “pump” wave with resonances in the plasma sheath induced by external radio waves to communicate through the plasma, effectively using the plasma sheath as an antenna for transmitting and receiving. Steps forward to further explore the feasibility of these techniques through laboratory experimentation and flight testing are proposed.

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Nov 12th, 11:00 AM Nov 12th, 11:15 AM

Solutions to the radio blackout effect of plasma sheaths at hypersonic and reentry velocities

Surge 172

Airborne vehicles traveling through an atmosphere at hypersonic velocities, especially in excess of Mach 15, face significant atmospheric heating that produces a plasma sheath which surrounds the vehicle, making communication to and from the hypersonic vehicle difficult or impossible. Various methods of communicating through the plasma sheath have been proposed and studied since the early 1960’s, yet a single elegant solution has not been found in unclassified research to date. These solutions can be divided into two basic types: passive methods, which minimize blackout conditions through the vehicle or mission design, and active methods, which use active systems to change or exploit the properties of the plasma flow field to communicate through the plasma barrier. Two active methods are presented as particularly likely to provide a solution which minimizes impact on vehicle performance and design while remaining effective. In the first, E × B Lorentz forces are used to create "windows" in the plasma through which radio communication is possible. Initial laboratory and simulation results indicate this technique could present a good solution. A second method that has been theoretically studied to date uses Raman interactions of an electromagnetic “pump” wave with resonances in the plasma sheath induced by external radio waves to communicate through the plasma, effectively using the plasma sheath as an antenna for transmitting and receiving. Steps forward to further explore the feasibility of these techniques through laboratory experimentation and flight testing are proposed.