Self‐consistent modeling of the large‐scale distortions in the geomagnetic field during the 24–27 September 1998 major magnetic storm

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94715/1/jgra17531.pd

High-latitude electrojets and auroral luminosity and auroral particle precipitations

The mutual location of high-latitude electrojets, typical regions of the auroral luminosity and regions of auroral energy particle participations into the upper atmosphere under substorm conditions are considered. Three electrojets exist at high latitudes during substorm intervals: WE - westward electrojet, EE - eastward electrojet and PE – polar electrojet. Geomagnetic latitudes of the WE/EE and PE location vary depend on local time and magnetic activity level, respectively. It is shown that the WE is located within the limits of the auroral oval precipitation (AOP), the EE in the evening sector is located within the diffuse auroral zone (DAZ) and the PE near noon is located at the poleward AOP boundary shifting poleward with decreasing the magnetic activity level. The relationship of electrojets with different plasma domains in the magnetosphere is discussed.QC 2012032

Auroral electrojets and 3D currents in the ionosphere-magnetosphere system

There are shortly described results of the analysis of variations in the location and intensity of the auroral electrojets during magnetic storms and substorms using a numerical method for estimating the equivalent ionospheric currents based on data from meridian chains of magnetic observatories. It is shown that the westward electrojet adjoins to the polar electrojet located at cusp latitudes in the dayside sector. The association of electrojets with the field-aligned currents (FACs), namely Region 1 FAC and Region 2 FAC is considered. During intense disturbances a Region 3 FAC (accompanied with diffuse electron precipitation from the plasma sheet boundary layer) with the downward current was identified. The analysis of observational data is summarized in terms of 2D time-latitude distribution of electrojets at ionospheric altitudes. The magnetic field sawtooth variations generated during the storm main and early recovery phases are also discussed. To follow 3D currents in the magnetosphereionosphere system a clarified view of interrelated 3D currents and magnetospheric plasma domains is presented.QC 2012032

The creation of families : Christianity and contemporary adoption

This thesis is a theological and practical reflection on the practice of adoption in contemporary Britain, as it affects Christian adoption agencies, Christian social workers, Christian parents and adopted children. The first three chapters set the background context to the research by examining the history, theology, legal and sociological context. This enables the contemporary situation to be established, particularly the potential for tension between the thinking of many Christians about constructing adoptive families and the open, liberal stance of the state and Local Authorities. This tension was heightened with the passing of the Adoption and Children Act 2002 that drew attention to radically different viewpoints within adoption work. The theological reflection methods employed were the pastoral cycle and canonical narrative, both of which were subordinate to an overall theology of engagement that enabled the interface between the Christian and non-Christian work in adoption to be investigated. The methodological approaches taken enabled quantitative and qualitative material to be combined. Three surveys were distributed: two to Christian groups, agencies and parents, involved in adoption work and one to adoption social workers. Secondly, telephone interviews were conducted. Data was also collected from a wide range of Internet websites. Fourthly, data was gathered from literature distributed by adoption agencies. A chapter (4) on Christian Adoption Agencies develops a theoretical agency that relates to the Church and the contemporary adoption system. Differences between historically different denominational emphases in adoption work and the present day reality is described. It continues to be possible for Christian adoption agencies to be relevant and specialised in this work. Central to all adoption work is the child: their future stability and happiness. This is examined by focussing upon the impact of the Christian faith on the potential for healing and wholeness for an adopted child (chapter 5). Three specific aspects of life are explored: an adopted child’s spirituality, identity and nurture. This discussion naturally leads into a further discussion about prospective and actual adoptive parents: the manner in which the Christian faith has a bearing upon adoption before, during and after the adoption of a child (chapter 6). Finally, Christian people within and without adoption work have been challenged about the nature of the family in the adoptive context. ‘Families’ that are accepted by the general population can be tolerated by some Christians yet discredited by others. The question is asked whether newly created adoptive families can have forms that are radically different from traditional patterns (chapter 7). This thesis concludes that Christians are making a contribution to adoption work that could be said to be distinctive. This said the Church should work to promote adoption of children with more confidence and debate less about adopters. This is a bold and contentious statement yet I contend that adoption could and should be a characterising motif of Christian family life.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Auroral electrojets and boundaries of plasma domains in the magnetosphere during magnetically disturbed intervals

We investigate variations in the location and intensity of the auroral electrojets during magnetic storms and substorms using a numerical method for estimating the equivalent ionospheric currents based on data from meridian chains of magnetic observatories. Special attention was paid to the complex structure of the electrojets and their interrelationship with diffuse and discrete particle precipitation and field-aligned currents in the dusk sector. During magnetospheric substorms the eastward electrojet (EE) location in the evening sector changes with local time from cusp latitudes (Φ~77°) during early afternoon to latitudes of diffuse auroral precipitation (Φ~65°) equatorward of the auroral oval before midnight. During the main phase of an intense magnetic storm the eastward currents in the noon-early evening sector adjoin to the cusp at Φ~65° and in the pre-midnight sector are located at subauroral latitude Φ~57°. The westward electrojet (WE) is located along the auroral oval from evening through night to the morning sector and adjoins to the polar electrojet (PE) located at cusp latitudes in the dayside sector. The integrated values of the eastward (westward) equivalent ionospheric current during the intense substorm are ~0.5 MA (~1.5 MA), whereas they are 0.7 MA (3.0 MA) during the storm main phase maximum. The latitudes of auroral particle precipitation in the dusk sector are identical with those of both electrojets. The EE in the evening sector is accompanied by particle precipitation mainly from the Alfvén layer but also from the near-Earth part of the central plasma sheet. In the lower-latitude part of the EE the field-aligned currents (FACs) flow into the ionosphere (Region 2 FAC), and at its higher-latitude part the FACs flow out of the ionosphere (Region 1 FAC). During intense disturbances, in addition to the Region 2 FAC and the Region 1 FAC, a Region 3 FAC with the downward current was identified. This FAC is accompanied by diffuse electron precipitation from the plasma sheet boundary layer. Actually, the triple system of FAC is observed in the evening sector and, as a consequence, the WE and the EE overlap. The WE in the evening sector comprises only the high-latitude periphery of the plasma precipitation region and corresponds to the Hall current between the Region 1 FAC and Region 3 FAC. During the September 1998 magnetic storm, two velocity bursts (~2–4 km/s) in the magnetospheric convection were observed at the latitudes of particle precipitation from the central plasma sheet and at subauroral latitudes near the ionospheric trough. These kind of bursts are known as subauroral polarization streams (SAPS). In the evening sector the Alfvén layer equatorial boundary for precipitating ions is located more equatorward than that for electrons. This may favour northward electric field generation between these boundaries and may cause high speed westward ions drift visualized as SAPS. Meanwhile, high speed ion drifts cover a wider range of latitudes than the distance between the equatorward boundaries of ions and electrons precipitation. To summarize the results obtained a new scheme of 3-D currents in the magnetosphere-ionosphere system and a clarified view of interrelated 3-D currents and magnetospheric plasma domains are proposed

Polar Geophysical

Abstract. There are shortly described results of the analysis of variations in the location and intensity of the auroral electrojets during magnetic storms and substorms using a numerical method for estimating the equivalent ionospheric currents based on data from meridian chains of magnetic observatories. It is shown that the westward electrojet adjoins to the polar electrojet located at cusp latitudes in the dayside sector. The association of electrojets with the field-aligned currents (FACs), namely Region 1 FAC and Region 2 FAC is considered. During intense disturbances a Region 3 FAC (accompanied with diffuse electron precipitation from the plasma sheet boundary layer) with the downward current was identified. The analysis of observational data is summarized in terms of 2D time-latitude distribution of electrojets at ionospheric altitudes. The magnetic field sawtooth variations generated during the storm main and early recovery phases are also discussed. To follow 3D currents in the magnetosphereionosphere system a clarified view of interrelated 3D currents and magnetospheric plasma domains is presented. 1

Global energy deposition during the January 1997 magnetic cloud event

The passage of an interplanetary magnetic cloud at Earth on January 10–11, 1997, induced significant geomagnetic disturbances, with a maximum AE in excess of 2000 nT and a minimum Dst of about −85 nT. We use a comprehensive set of data collected from space-borne instruments and from ground-based facilities to estimate the energy deposition associated with the three major magnetospheric sinks during the event. It is found that averaged over the 2-day period, the total magnetospheric energy deposition rate is about 400 GW, with 190 GW going into Joule heating rate, 120 GW into ring current injection, and 90 GW into auroral precipitation. By comparison, the average solar wind electromagnetic energy transfer rate as represented by the ε parameter is estimated to be 460 GW, and the average available solar wind kinetic power USW is about 11,000 GW. A good linear correlation is found between the AE index and various ionospheric parameters such as the cross-polar-cap potential drop, hemisphere-integrated Joule heating rate, and hemisphere-integrated auroral precipitation. In the northern hemisphere where the data coverage is extensive, the proportionality factor is 0.06 kV/nT between the potential drop and AE, 0.25 GW/nT between Joule heating rate and AE, and 0.13 GW/nT between auroral precipitation and AE. However, different studies have resulted in different proportionality factors. One should therefore be cautious when using empirical formulas to estimate the ionospheric energy deposition. There is an evident saturation of the cross-polar-cap potential drop for large AE (\u3e1000 nT), but further studies are needed to confirm this