Properties of a large-scale flux rope and current sheet region on the dayside of Mars: MGS MAG/ER and MEX ASPERA-3 ELS observations

We present dual spacecraft observations by MGS MAG/ER and MEX ASPERA-3 ELS of a large-scale magnetic flux rope on the dayside of Mars that occurs in close proximity to the crustal magnetic fields and a dayside current sheet region. A current sheet (including the large-scale flux rope) was observed on repeated MGS orbits when the draped solar wind magnetic field present in the ionosphere had a +B component (in MSO). Minimum Variance Analysis (MVA) of the large-scale flux rope and two current sheet crossings that occur after show a common peak in magnetic field along the intermediate variance direction, indicating the normal component of a reconnecting current sheet. All repeated orbits demonstrated evidence of a plasma boundary by the decrease in electron differential flux above 100eV when moving into regions dominated by the crustal magnetic field, and coincided with the measured magnetic field strength being double the undisturbed crustal magnetic field. We argue this forms evidence of magnetic reconnection between crustal magnetic fields and draped solar wind magnetic field (from ionosphere or magnetosheath) at a "mini-magnetopause" type boundary on the dayside of Mars. Similar electron pitch angle distributions observed during the large-scale flux rope, current sheet crossings, and regions of radial crustal magnetic field, suggest these regions share a common magnetic field topology for the trapping of magnetosheath particles on open crustal magnetic fields on the dayside of Mars. As such, indicates a trapping quadrupole magnetic field exist either at the magnetic reconnection X-line region or where open crustal magnetic fields meet oppositely directed solar wind magnetic field. At a time when the draped solar wind magnetic field present in the ionosphere was weaker in strength, the current sheet crossing was observed over an extended region of 2000km. The extended current sheet demonstrated properties of a hot diamagnetic region and features of a mirror mode structure or magnetic hole, the first time such a structure has been found in the ionosphere of Mars. Observations suggests lower energy electrons could be accelerated by a local process of perpendicular heating/pitch angle diffusion and supports similar results at the Earth's polar cusp reported by Nykyri et al. (Nykyri et al. [2012]. J. Atmos. Sol-Terr. Phys. 87, 70). Such large scale and energetic structures are usually associated with regions beyond a planet's ionosphere, and the occurrence within the ionosphere of Mars may have an important impact on escape processes and the evolution of the martian atmosphere

Electron flux models for different energies at geostationary orbit

Forecast models were derived for energetic electrons at all energy ranges sampled by the third-generation Geostationary Operational Environmental Satellites (GOES). These models were based on Multi-Input Single-Output Nonlinear Autoregressive Moving Average with Exogenous inputs methodologies. The model inputs include the solar wind velocity, density and pressure, the fraction of time that the interplanetary magnetic field (IMF) was southward, the IMF contribution of a solar wind-magnetosphere coupling function proposed by Boynton et al. (2011b), and the Dst index. As such, this study has deduced five new 1 h resolution models for the low-energy electrons measured by GOES (30–50 keV, 50–100 keV, 100–200 keV, 200–350 keV, and 350–600 keV) and extended the existing >800 keV and >2 MeV Geostationary Earth Orbit electron fluxes models to forecast at a 1 h resolution. All of these models were shown to provide accurate forecasts, with prediction efficiencies ranging between 66.9% and 82.3%

On the origins of magnetic flux ropes in near-Mars magnetotail current sheets

International audienceWe analyze Mars Atmosphere and Volatile EvolutioN (MAVEN) observations of magnetic flux ropes embedded in Martian magnetotail current sheets, in order to evaluate the role of magnetotail reconnection in their generations. We conduct a minimum variance analysis to infer the generation processes of magnetotail flux ropes from the geometrical configuration of the individual flux rope axial orientation with respect to the overall current sheet. Of 23 flux ropes detected in current sheets in the near-Mars (∼1-3 Martian radii downstream) magnetotail, only 3 (possibly 4) can be explained by the magnetotail reconnection scenario, while the vast majority of the events (19 events) are more consistent with flux ropes that are originally generated in the dayside ionosphere and subsequently transported into the nightside magnetotail. The mixed origins of the detected flux ropes imply complex nature of generation and transport of Martian magnetotail flux ropes

Heightening Tension in Relations between Trade Unions and the Labour Government in 2002

During 2002 tension between trade unions and the Labour government reached a level not seen before in their relationship. This review examines the source of the tension and its manifestations. It shows that during the year a range of issues emerged that divided the government and unions. New Labour 'modernizers' cited these differences as reasons to further distance the Party from trade unions. The article argues that relations between trade unionism and the government are at low ebb, and that the extent of disagreement between the two is now more pronounced than at any other time since 1997. Copyright Blackwell Publishing Ltd/London School of Economics 2003..