Description: The LFMG instrument is used to make extremely high resolution scalar magnetic field and difference measurements at the Earthfs surface. The Phase 1 effort included development of a conceptual design and established the feasibility of designing, fabricating and demonstrating in Phase 2 two prototype LFMG instruments for use in a gradiometer configuration. The Phase 1 LFMG conceptual design includes a technical plan for approaching 10 fT/ãHz resolution in the LFMG prototype. The breadboard LFMG demonstrated measurements of scalar field variations with a resolution of 45 fT/ãHz in Phase 1. The LFMG has stability required to measure vector gradients (difference of scalar measurements between two LFMG instruments on the Earthfs surface) with very high stability over distances of the order of kilometers. The LFMG prototype will have a dynamic range of 25,000 nT to 75,000 nT, and achieves an accuracy and stability necessary to perform common mode noise rejection between two LFMG instruments. This advance in the state of the art represents an increase in sensitivity of more than an order of magnitude, and will permit new high performance gradiometer measurements for use in innovative exploratory research into the effects producing temporal variations in the magnetic field over the Earthfs surface.

Benefits: The LFMG with its extremely high sensitivity and stability will have a variety of commercial and military applications. including measurement of the magnetic fields at the Earth's surface for geophysical airborne and marine prospecting. The LFMG can serve as the new standard for geomagnetic observatories. The LFMG instruments can be used to investigate surface and magnetospheric effects before and after earthquakes and volcanic activity. The LFMG can technology can be used in the next generation high-sensitivity magnetometers to be used by the US Navy for submarine detection and mine countermeasures applications. The LFMG instruments will add high resolution ELF capability for solving DoD magnetic detection problems. The miniaturized LFMG sensor will have applications in UAVs used for sea and land surveillance for submarines, tanks under trees, tunnels, and underground facilities. The LFMG characteristics of outstanding accuracy and high-frequency signal response will open up a variety of applications in commercial security and surveillance applications.

The accurate measurement of the magnetic field components and their orientation in space is recognized as a basic requirement for space research. The LFMG will be used to observe magnetic fields at the Earthfs surface with extremely high resolution. The major features of the LFMG that set it apart from other magnetic measurement systems are its outstanding accuracy and its ability to difference scalar measurements at many kilometers separation. LFMG magnetic field measurements provide means for studying the structure and dynamics of Earthfs interior. On the Earth and other planets, the magnetic field provides unique information on the structure and dynamics of the planetary interior, fluid flow within and upon its surface, and the influence of the solar environment. The LFMG can be used for extremely high resolution investigations of geopotential changes in the Earthfs crust associated with earthquakes and volcanic activity and eruptions.