Early Soviet satellite magnetic field measurements in the years 1964 and 1970

We present a collection of magnetic field absolute measurements performed by the early Soviet magnetic satellite missions Kosmos-49 (1964) and Kosmos-321 (1970). A total of 17 300 measured values are available for the Kosmos-49 mission, covering homogeneously 75 % of the Earth's surface between 49∘ latitude north and south. About 5000 measured values are available for the Kosmos-321 mission, covering homogeneously 94 % of the Earth's surface between 71∘ latitude north and south. The data are available at PANGAEA (Krasnoperov et al., 2020, https://doi.org/10.1594/PANGAEA.907927).

Early Soviet satellite magnetic field measurements over 1964 and 1970

We present the collection of magnetic field absolute measurements performed by early Soviet magnetic satellite missions Kosmos-49 (1964) and Kosmos-321 (1970). Totally 17300 measured values are available for Kosmos-49 mission, covering homogeneously 75 % of the Earth's surface between 49° north and south latitude. About 5000 measured values are available for Kosmos-321 mission, covering homogeneously 94 % of the Earth's surface between 71° north and south latitude.

Non-collinear antiferromagnetism in FeCrAs Special issue on Neutron Scattering in Canada.

FeCrAs undergoes a magnetic ordering transition at TN ≃ 125 K. The magnetic structure of FeCrAs, which crystallizes in space group [Formula: see text] and is isostructural to Fe2P, was determined by constant wavelength neutron powder diffraction. A single basis function was found to describe the intensity distribution in the magnetic satellite reflections, which are associated with propagation vector k = (1/3, 1/3, 0), representing a K-point zone-boundary ordering. The magnetic intensity could be modelled by moments from Cr only, which lie on the 3g-sites, in pyramidal coordination by As, whereas the moments on Fe, in tetrahedral coordination on the 3f-sites, were found to be so small as to be zero within error. This agrees with previous Mössbauer spectroscopy measurements on this compound. The magnetic structure is characterized by non-collinear antiferromagnetic order of the moments, all of which lie in the hexagonal plane. This does not appear to have been observed in other monopnictides with Fe2P structure but is consistent with geometric frustration of antiferromagnetic interactions.

A model for estimating the relation between the Hall to Pedersen conductance ratio and ground magnetic data derived from CHAMP satellite statistics

The goal of this study is to find a way to statistically estimate the Hall to Pedersen conductance ratio α from ground magnetic data. We use vector magnetic data from the CHAMP satellite to derive this relation. α is attained from magnetic satellite data using the 1-D Spherical Elementary Current Systems (SECS). The ionospheric equivalent current density can either be computed from ground or satellite magnetic data. Under the required 1-D assumption, these two approaches are shown to be equal, which leads to the advantage that the statistics are not restricted to areas covered by ground data. Unlike other methods, using magnetic satellite measurements to determine α ensures reliable data over long time sequences. The statistical study, comprising over 6000 passes between 55° and 76.5° northern geomagnetic latitude during 2001 and 2002, is carried out employing data from the CHAMP satellite. The data are binned according to activity and season. In agreement with earlier studies, values between 1 and 3 are typically found for α. Good compatibility is found, when α attained from CHAMP data is compared with EISCAT radar measurements. The results make it possible to estimate α from the east-west equivalent current density Jφ; [A/km]: α=2.07/(36.54/|Jφ|+1) for Jφ<0 (westward) and α=1.73/(14.79/|Jφ+1) for Jφ0 (eastward). Using the same data, statistics of ionospheric and field-aligned current densities as a function of geomagnetic latitude and MLT are included. These are binned with respect to activity, season and IMF BZ and BY. For the first time, all three current density components are simultaneously studied this way on a comparable spatial scale. With increasing activity, the enhancement and the equatorward expansion of the electrojets and the R1 and R2 currents is observed, and in the nightside, possible indications of a Cowling channel appear. During southward IMF BZ, the electrojets and the R1 and R2 currents are stronger and clearer than during northward BZ. IMF BY affects the orientation of the pattern.