https://nova.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:3461 Wed 24 Jul 2013 22:22:24 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:3432 Wed 24 Jul 2013 22:22:16 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:7916 0.]]> Wed 11 Apr 2018 13:26:57 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:11505 y/B_z)) since this governs the spatial morphology of the currents. The Birkeland current densities were then corrected for variations in EUV-produced ionospheric conductance by normalizing the current densities to those occurring for 0° dipole tilt. To determine the dependence of the currents on other solar wind variables for a given IMF clock angle, the data were then sorted sequentially by the following parameters: the solar wind electric field in the plane normal to the Earth–Sun line, E_yz; the solar wind ram pressure; and the solar wind Alfvén Mach number. The solar wind electric field is the dominant factor determining the Birkeland current intensities. The currents shift toward noon and expand equatorward with increasing solar wind electric field. The total current increases by 0.8 MA per mV m⁻¹ increase in E_yz for southward IMF, while for northward IMF it is nearly independent of the electric field, increasing by only 0.1 MA per mV m⁻¹ increase in E_yz. The dependence on solar wind pressure is comparatively modest. After correcting for the solar dynamo dependencies in intensity and distribution, the total current intensity increases with solar wind dynamic pressure by 0.4 MA/nPa for southward IMF. Normalizing the Birkeland current densities to both the median solar wind electric field and dynamic pressure effects, we find no significant dependence of the Birkeland currents on solar wind Alfvén Mach number.]]> Wed 11 Apr 2018 11:29:24 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:1996 1.3 km s⁻¹ (>77 mVm⁻¹) occurred during a ~ 5-min velocity spike, peaking at 10:40 UT during the expansion phase. The drifts decayed rapidly to ~ 300 ms⁻¹ (18 mVm⁻¹) during the 6-min recovery phase interval, 11:04 to 11:10 UT. Overall, the AWFC had a lifetime of 74 min, and was located near -65° Λ in the evening sector west of the Harang discontinuity. The large westward drifts were confined to a geographic zonal channel of longitudinal ex-tent >20° (>1.3 h magnetic local time), and latitudinal width ~2° Λ. Using a half-width of ~ 100 km in latitude, the peak electric potential was >7.7 kV. However, a transient velocity of >3.1 km s⁻¹ with potential >18.4 kV was observed further poleward at the end of the recovery phase. Auroral oval boundaries determined using DMSP measurements suggest the main flow channel overlapped the equatorward boundary of the diffuse auroral oval. During the ~ 2-h interval following the flow channel, an ~ 3° Λ wide band of scatter was observed drifting slowly toward the west, with speeds gradually decaying to ~ 50 ms⁻¹ (3 mVm ⁻¹). The scatter was observed extending past the Harang discontinuity, and had Doppler signatures characteristic of the main ionospheric trough, implicating the flow channel in the further depletion of F-region plasma. The character of this scatter was in contrast with the character of the scatter drifting toward the east at higher latitude.]]> Wed 11 Apr 2018 10:35:42 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:1127 Sat 24 Mar 2018 08:32:03 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:6248 Sat 24 Mar 2018 07:48:40 AEDT ]]>