magnetoionic duct

magnetoionic duct

[mag¦nēd·ō·ī′än·ik ′dəkt]
(geophysics)
Duct along the geomagnetic lines of force which exhibits waveguide characteristics for radio-wave propagation between conjugate points on the earth's surface.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.