Magnetic Fields Generated by Internal Ocean Seawater Motion

• Main Author: Davis, Charles A.
• Other Authors: NAVAL POSTGRADUATE SCHOOL MONTEREY CA
• Format: Text
• Language: English
• Published: 1991
• Subjects: Physical and Dynamic Oceanography; Electricity and Magnetism; *MAGNETIC FIELDS; *INTERNAL WAVES; GEOMAGNETISM; SOURCES; MEASUREMENT; MODELS; LAYERS; MOTION; THESES; TURBULENCE; CURRENT DENSITY; VARIATIONS; INTERNAL; NOISE; OCEANS; MAXWELLS EQUATIONS; SEA WATER; ARCTIC REGIONS; MAGNETIC ANOMALY DETECTION; *SEA WATER; *OCEANS; *MOTION; OCEAN WAVES; OCEAN CIRCULATION; TURBULENT FLOW; WATER FLOW; MASS FLOW; ELECTROMAGNETIC FIELDS; Arctic
• Online Access: http://www.dtic.mil/docs/citations/ADA246589; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA246589

This thesis models induced magnetic fields from the motion of seawater in the Earth's magnetic field analytically and compares the results to arctic on-the-ice magnetic fluctuation measurements. The oceans have various types of internal motions, such as internal waves and turbulence. This motion of sea water, which is a conductor, in the earth's magnetic field induces a current density. The current density, in turn, induces its own magnetic field. This thesis models internal waves and upper layer ocean turbulence analytically. The corresponding induced magnetic fields are calculated using a static form of Maxwell's equations and parameters for the Arctic are inserted. comparisons are made with measurements from the Arctic Internal Wave Experiment (1985). The predicted fields from internal waves have magnitudes that are measureable and of the same order of magnitude as ionospherically generated fields, The predicted fields from turbulence are several orders of magnitude smaller than ionospherically generated fields. Besides giving information about internal motions in the ocean, the seawater induced fields are a noise source in magnetic anomaly detection.