Explosive-driven ferromagnetic generator

An explosive-driven ferromagnetic generator (EDFMG, explosively pumped ferromagnetic generator, EPFMG, or FMG) is a compact <a href="/facts/Pulsed_power/BTJN8xg5">pulsed power</a> generator, a device used for generation of short high-<a href="/facts/Voltage/EN2po6N2">voltage</a> high-<a href="/facts/Electric_current/Dc1xdnUX">current</a> pulse by releasing energy stored in a <a href="/facts/Permanent_magnet/vvrg6VSk">permanent magnet</a>. It is suited for delivering high-<a href="/facts/Electric_current/Dc1xdnUX">current</a> pulses (kiloamperes) to low-<a href="/facts/Electrical_impedance/I06NSXtN">impedance</a> <a href="/facts/Electrical_load/IX0XBAqB">loads</a>.
The FMGs consist of a permanent magnet (usually a <a href="/facts/Neodymium_magnet/1LApJ5Xq">neodymium magnet</a>), a <a href="/facts/High_explosive/sUme5Pp8">high explosive</a> charge, and a <a href="/facts/Electromagnetic_coil/fk2ElSDk">pickup coil</a>. They are a kind of <a href="/facts/Phase_transition/eLP2BY8R">phase transition</a> generators, utilizing pressure-induced magnetic phase transition effect. By adjusting the number of turns of the coil, which can be as low as a single turn, the generator can be designed for delivery of high-current low-voltage pulses or, with more turns, low-current high-voltage pulses.
The <a href="/facts/Shock_wave/CqrG1Xm5">shock wave</a> generated by explosion destroys the <a href="/facts/Magnetic_domain/f7KTN10R">magnetic domains</a> in the magnet, cause loss of the <a href="/facts/Magnetic_field/Ta8Ev588">magnetic field</a>, and the very sudden change induces a high-peak <a href="/facts/Electric_current/Dc1xdnUX">electric current</a> in the surrounding coil. Both the shock wave directions parallel to the vector of magnetization (longitudinal) and perpendicular (transverse) are possible to be used. One of the possible configurations is a ring magnet with the explosive charge in its center.
EDFMGs are especially well suited as seed power sources for <a href="/facts/Explosively_pumped_flux_compression_generator/uEq7thDb">explosively pumped flux compression generators</a> and can be used for charging capacitor banks.
A generator coupling an EDFMG containing an 8.75 cm3 of magnetic material with a spiral <a href="/facts/Vector_inversion_generator/vdXT7e6p">vector inversion generator</a> yielded a pulse of amplitude over 40 kilovolts with a <a href="/facts/Rise_time/m9VVn393">rise time</a> of 6.2 nanoseconds. Generators delivering pulses over 50 kV and 5 kA were demonstrated.
Ultra-compact generators with diameter less than 50 mm were developed.

Explosive-driven ferromagnetic generator open-in-new

Explosive-driven ferromagnetic generator