THE PROSPECTS FOR ACTIVE SHIELDING

Technical Report · Thu Nov 01 04:00:00 EST 1962

OSTI ID:4729651

Levy, R H

A review is given of the reasons for the interest in active shielding and the types of missions for which an active shield would be particularly desirable are discussed. Recent work on active shielding is reviewed. Electrostatic shielding is discussed. In general, the maintenance of an electrostatic field for shielding purposes will require the expenditure of power owing to the presence of a neutral highly conducting plasma. Estimates of the power required are extremely high, and electrostatic shielding appears unattractive. Magnetic shielding is also discussed. The virial theorem on the weights of magnetic field coils in space is explained, and it is shown how this theorem can be used to make a direct comparison between the use of a material as an element in a structure and as a stopping material for energetic protons. The result of this comparison is that for sufficiently large sizes magnetic shielding will always be superior, but that the sizes involved are extremely large. The way in which the critical size scales with the strength to weight ratio for structural materials and the magnetic field strength is discussed. The status and prospects for large superconducting radiation shields are reviewed with particular emphasis on those features which are likely to make the minimum weights estimated by the virial theorem unduly optimistic. In conclusion, the possibility of shielding a space craft by blowing a hole in the interplanetary magnetic field (along which the protons move) with an atomic bomb is mentioned. It appears that such a shield would violate Liouville's theorem. (auth)

• Research Organization: Avco Corp. Avco-Everett Research Lab., Everett, Mass.
• NSA Number: NSA-17-010200
• OSTI ID: 4729651
• Report Number(s): NP-12371; AMP-94
• Country of Publication: United States
• Language: English

Related Subjects

BIBLIOGRAPHY
COILS
COSMIC RADIATION
ECONOMICS
ELECTRIC CONDUCTIVITY
ELECTRIC FIELDS
ELECTROSTATICS
LIOUVILLE THEOREM
MAGNETIC FIELDS
MAGNETISM
MAGNETOHYDRODYNAMICS
MATERIALS TESTING
MATHEMATICS
MECHANICAL STRUCTURES
MECHANICS
NUCLEAR EXPLOSIONS
ORBITS
PERSONNEL
PLANETS
PLASMA
POWER
PROTONS
RADIATION BELTS
RADIATION PROTECTION
RELATIVITY THEORY
SATELLITES
SHIELDING
SHIELDING MATERIALS
SLOWDOWN
SPACE
SPACE APPLICATIONS AND TECHNOLOGY
SPACE FLIGHT
SPACE VEHICLES
STATISTICS
SUPERCONDUCTIVITY
WEIGHT