A5011211267- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Earthquake Detection and Analysis
- Astro and Planetary Science
- Planetary Science and Exploration
- Magnetic Field Sensors Techniques
- Non-Destructive Testing Techniques
- Sensor Technology and Measurement Systems
- Cryptographic Implementations and Security
- Geophysics and Gravity Measurements
Technische Universität Braunschweig
2015-2019
The long duration of the Rosetta mission allows us to study evolution diamagnetic cavity at comet 67P/Churyumov–Gerasimenko in detail. From 2015 April 2016 February 665 intervals could be identified where was located a zero-magnetic-field region. We temporal and spatial distribution this its boundary conclude that properties depend on long-term trend outgassing rate, but do not respond transient events spacecraft location, such as outbursts or high neutral densities. Using an empirical model...
Abstract. We report on magnetic field measurements made in the innermost coma of 67P/Churyumov-Gerasimenko its low-activity state. Quasi-coherent, large-amplitude (δ B/B ~ 1), compressional oscillations at 40 mHz dominate immediate plasma environment nucleus. This differs from previously studied cometary interaction regions where waves ion gyro-frequencies are main feature. Thus classical pickup-ion-driven instabilities unable to explain observations. propose a cross-field current...
Abstract Ultralow frequency (ULF) waves generated in the ion foreshock are a well‐known source of Pc3‐Pc4 (7–100 mHz) observed dayside magnetosphere. We use data acquired on 10 April 2013 by multiple spacecraft to demonstrate that ULF upstream origin can propagate midnight sector inner At 1130–1730 UT selected day, two Van Allen Probes and geostationary ETS‐VIII satellite detected compressional 20 40 mHz magnetic field oscillations between L ∼ 4 7 sector, along with other located closer...
Abstract. This study presents an investigation on the occurrence of fast flows in magnetotail using complete available data set THEMIS spacecraft for years 2007 to 2015. The flow events (times enhanced ion velocity) are detected through use a velocity criterion, therefore making resulting database as large almost 16 000 events. First, basic statistical findings concerning distributions, rates, group structures presented. Second, Superposed Epoch Analysis is utilized account average profiles...
Fluxgate magnetometers on-board spacecraft need to be regularly calibrated in flight. In low fields, the most important calibration parameters are three offset vector components, which represent magnetometer measurements vanishing ambient magnetic fields. case of three-axis stabilized spacecraft, a few methods exist determine offsets: (i) by analysis Alfvénic fluctuations present pristine interplanetary field, (ii) rolling around at least two axes, (iii) cross-calibration against from...
Abstract In this study, we analyze the first conjugate observation of auroral finger‐like structures using ground‐based all‐sky cameras and Time History Events Macroscale Interactions during Substorms (THEMIS) satellites investigated associated physical processes that are a cause fragmentation into patches. Two events reported: one is event, other nearly event. The event was observed at Narsarsuaq (magnetic latitude: 65.3°N), Greenland, 0720–0820 UT (0506–0606 LT) on 17 February 2012....
Abstract. A newly developed method for determining spin axis offsets of magnetic field instruments on spacecraft is applied to THEMIS. The formerly used determination method, relying solar wind Alfvénic fluctuations, was rarely applicable due the orbital restrictions mission. With new procedure, based observation mirror modes in magnetosheath, updated can be estimated approximately once per year. Retrospective calibration all THEMIS measurements thereby made possible. Since, up this point,...
Abstract. Different magnetopause models with a diverse level of complexity are in use. One thing that they have common is mainly based on near-earth observations; i.e. use measurements at distances about ±10 Earth radii along the GSM x axis. Only very few observations crossings larger used for model fitting. In this study we compare position and normal direction predictions Shue et al. (1997) actual identified using ARTEMIS spacecraft lunar distance, 60 radii. We find differences location...
Abstract. Multi-spacecraft data from the years 2008 to 2015 of THEMIS mission particularly in near-Earth plasma sheet are used order empirically determine polytropic index quiet and active time magnetotail. The results a number previous studies 1990s can be confirmed. An analysis total database, although showing poor correlation, an average γ = 1. 72. is well correlated with 49. However, scattering suggests that not adequate. In reduce timescales, individual spacecraft orbits analyzed,...
Abstract In this work, observations of multispacecraft mission Time History Events and Macroscale Interactions during Substorms are used for statistical investigation dipolarization fronts in the near‐Earth plasma sheet magnetotail. Using very stringent criteria, 460 events detected almost 10 years data. Minimum variance analysis is to determine normal directions phase fronts, providing evidence existence a natural symmetry these phenomena, given by neutral This finding enables definition...
Abstract. We statistically analyzed severe magnetic fluctuations in the nightside near-Earth plasma sheet at 6–12 RE (Earth radii; 1 = 6371 km), because they are important for non-magnetohydrodynamics (non-MHD) effects magnetotail and considered to be necessary current disruption inside-out substorm model. used field data from 2013 2014 obtained by Time History of Events Macroscale Interactions during Substorms E (THEMIS-E) satellite (sampling rate: 4 Hz). A total 1283 fluctuation events...
Abstract. Different magnetopause models with a diverse level of complexity are in use. They have common to be mainly based on near-earth observations, i.e., they use measurements at distances about ±10 Earth radii. Only very few observations crossings larger used for model fitting. In this study we compare position and direction pre- dictions the Shue et al. (1997) actual identified using 5 ARTEMIS spacecraft lunar distance, 60 We find good agreement between prediction observation position....