Generation of ULF by a horizontal electric dipole


  • Carl Greifinger,

  • Phyllis Greifinger


A horizontal electric dipole antenna at the ground operating at ULF can excite hydromagnetic TE waves in the hydromagnetic waveguide centered at the F2 ionization maximum. Propagation in the waveguide accompanied by leakage into the earth-ionosphere cavity provides a mechanism by which magnetic fluctuations may be transmitted to ground receivers some thousands of kilometers from the transmitter. At ULF, the optimum direction for this mode of operation is broadside to the dipole. Under favorable ionospheric conditions, a dipole 30 km in length and driven at a peak current of 500 amp could produce a ground signal of the order of a milligamma at a distance of 2000 km.