Annales Geophysicae (ANGEO) is an international, multi- and inter-disciplinary scientific open-access journal in the field of solar–terrestrial physics. ANGEO publishes original articles and short communications (letters) in the sciences of the Sun–Earth system, including the science of space weather, the solar–terrestrial plasma physics, and the Earth's atmosphere.
Authors from the Technical University Darmstadt will profit from a new institutional agreement with Copernicus Publications starting 1 January 2017. The agreement which is valid for corresponding authors enables a direct settlement of article processing charges (APCs) between the university and the publisher.
A new type of wave has been detected by the magnetometer of the Rosetta spacecraft close to comet P67/Churyumov-Gerasimenko. We provide the analytical model of this wave excitation from linear perturbation theory. A modified ion-Weibel instability is identified as source of this wave excited by a cometary current. The waves predominantly grow perpendicular to this current. A fan-like phase structure results from superposing the strongest growing waves in a cometary rest frame.
P. Meier, K.-H. Glassmeier, and U. Motschmann
This study presents an investigation on the occurrence of fast flows in the magnetotail using the complete available data set of the THEMIS spacecraft for the years 2007 to 2015. First, basic statistical findings concerning velocity distributions, occurrence rates, group structures and key features of 16 000 events are presented using Superposed Epoch and Minimum Variance Analysis techniques.
D. Frühauff and K.-H. Glassmeier
The method of electric field mapping along geomagnetic field lines, derived in an accompanying paper, is applied to the International Geomagnetic Reference Field. Formulae for the geomagnetic field gradient tensor are derived and these are used in a software package developed to map the electric field. A number of examples are presented illustrating the method. The method will be of importance in conjugate studies of ionospheric convection when the external magnetic field can be neglected.
A. D. M. Walker
This paper introduces a new method for mapping electric fields in the magnetosphere along geomagnetic field lines. This is important for conjugate studies of electric fields measured in the ionosphere by SuperDARN radars, and at spacecraft carrying electric field probes. First elementary methods in a dipole field are reviewed and then the theory of of a new method described for general magnetic field models. The method is tested in a dipole model with a Harris magnetotail field.
A. D. M. Walker and G. J. Sofko
Adaptive magnetospheric models based on THEMIS magnetic observations made at 6-9Re in the nightside magnetosphere are used to map the magnetically conjugate 30 and 80keV proton isotropy boundaries (IBs) to investigate the value of Kib=Rc/rc (magnetic curvature radius to particle gyroradius) in the neutral sheet at the IB generation place. For the most accurate mapping, the group Kib spread spans from 4 to 32; its median value is ~13, slightly larger than Kib8 expected for current sheet scatter.
V. A. Sergeev, I. A. Chernyaev, V. Angelopoulos, and N.Y. Ganushkina