The results of measurements of magnetic and electric fields, plasma ions energy, and plasma density during the Russian-American North Star active experiment are presented. The experiment was carried out in the auroral ionosphere on 22 January 1999. A Black Brant XII rocket, having two explosive aluminum plasma generators plus scientific payloads onboard, was launched at 13:57:03 UT from Poker Flat, Alaska. Two plasma-jet injections across the magnetic field were made at the altitudes 280 and 360 km, respectively. Before injection 1, an air cloud was released to increase jet ionization. At injection 1, the maximum plasma density exceeded the density at injection 2 by two orders of magnitude. This can be explained by charge stripping of aluminum atoms when the jet propagated through the dense air cloud. Only at injection 1 was complete expelling of the magnetic field by the plasma jet observed. A weak plasma deceleration was indicated by magnetic field compression before the jet front. At injection 2, the magnetic field was weakened only by 1%. A polarization electric field E = − −V × × B generated field-aligned currents, which involved the ionospheric plasma in motion, and the plasma jet efficiently decelerated.
Nomenclature
B= magnetic field, nT E = electric field, V/cm E x , E y , E z = electric field components in the payload reference frame, V/cm l p = length of cylindrical Langmuir probe, mm m i = ion mass, amu n i = plasma density, cm −3 r p = radius of cylindrical Langmuir probe, mm V = plasma velocity, km/s V A = Alfvén velocity, km/s V p = bias of Langmuir probe, V δ B x , δ B y , δ B z = variation of magnetic field components in the payload reference frame, nT