Ground signatures of convecting reconnected flux tubes

摘要: The ground magnetic and ionospheric signatures of reconnected flux tubes have been modeled using an expanding rotating elliptical field-aligned current system. Assuming a constant total 2 × 105 A, initial field strengths ∼100 nT are shown to decay rapidly with distance from the system expansion. associated electric estimates show that tube footprint convects initially eastward or westward velocity decreasing 3 1 km s−1 then poleward 0.5 0.2 s−1. signature detected by magnetometer array will be 1-cycle oscillation period 8 min as through ionosphere above. These characterized rapid increase in strength, maximum amplitudes being reached within first 5 min, followed gradual decay. This modeling emphasizes temporal variation position recording respect image determines form signature. formalism should useful behavior at high latitudes may relevant dayside auroral observations.