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University of Newcastle Centre for Space Physics http://plasma.newcastle.edu.au/plasma. T wo-dimensional C ross-phase G radient Techniques - H igh-latitude Pc5 ULF M agnetometer D ata. S. T. Ables B. J. Fraser Centre for Space Physics School of Mathematical and Physical Sciences
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University of NewcastleCentre for Space Physicshttp://plasma.newcastle.edu.au/plasma Two-dimensional Cross-phase Gradient Techniques - High-latitude Pc5 ULF Magnetometer Data S. T. Ables B. J. Fraser Centre for Space Physics School of Mathematical and Physical Sciences The University of Newcastle AUSTRALIA
The “Davis Square” Cusp location ~75o MLat N (CGM) Magnetometer Array (Summer operation 2002, 2003, 2004)
Pc5 ULF waves dH/dt dD/dt
DAV-ZHS Cross-phase [Degrees] -90 90 0 Azimuthal pairs of stations were used to produce Cross-phase spectrograms There are both diurnal and frequency variations in cross-phase Frequency [mHz] Δ UT [Hour]
VYV-RIK Cross-phase [Degrees] -90 90 0 Cross-phase spectrograms for each azimuthally spaced pair of stations have clear differences. Particularly 2 hours each side of Local magnetic noon Frequency [mHz] Δ UT [Hour]
IMF control of field line topology – Bz Effect The Ф5 index: Phase difference between 2 azimuthally spaced stations Closed field lines
IMF control of field line topology – Bz~0 Closed field lines Anti-sunward azimuthal motion
IMF control of field line topology – Bz Negative Open field lines convective motion
IMF control of field line topology – Bz Variable Mixed - 0pen-closed field lines
