Recent highlights from Cluster, the first 3-D magnetospheric mission

Abstract. The Cluster mission has been operated successfully for 14 years. During this time period, the evolution of the orbit has enabled Cluster to sample many more magnetospheric regions than was initially anticipated. So far, the separation of the Cluster spacecraft has been changed more than 30 times and has ranged from a few kilometres up to 36 000 km. These orbital changes have enabled the science team to address a wide variety of scientific objectives in key regions of Earth's geospace environment: the solar wind and bow shock, the magnetopause, polar cusps, magnetotail, plasmasphere and the auroral acceleration region. Recent results have shed new light on solar wind turbulence. They showed that the magnetosheath can be asymmetric under low Mach number and that it can contain density enhancement that may affect the magnetosphere. The magnetopause was found to be thinner and to have a higher current density on the duskside than on the dawnside. New methods have been used to obtain characteristic of the magnetotail current sheet and high-temporal-resolution measurements of electron pitch angle within flux transfer events (FTEs). Plasmaspheric wind has been discovered, and the refilling of the plasmasphere was observed for the first time over a very wide range of L shells. New models of global electric and magnetic fields of the magnetosphere have been obtained where Cluster, due to its polar orbit, has been essential. Finally, magnetic reconnection was viewed for the first time with high-resolution wave and electron measurements and acceleration of plasma was observed during times of varying rate of magnetic reconnection. The analysis of Cluster data was facilitated by the creation of the Cluster Science Data System (CSDS) and the Cluster Science Archive (CSA). Those systems were implemented to provide, for the first time for a plasma physics mission, a long-term public archive of all calibrated high-resolution data from all instruments.

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The Location of Magnetic Reconnection at Earth’s Magnetopause

Space Science Reviews ◽

10.1007/s11214-021-00817-8 ◽

2021 ◽

Vol 217 (3) ◽

Author(s):

K. J. Trattner ◽

S. M. Petrinec ◽

S. A. Fuselier

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Magnetic Reconnection ◽

Ion Beams ◽

Review Article ◽

Observational Evidence ◽

Magnetic Shear ◽

General Direction ◽

Shear Model ◽

Wide Range

AbstractOne of the major questions about magnetic reconnection is how specific solar wind and interplanetary magnetic field conditions influence where reconnection occurs at the Earth’s magnetopause. There are two reconnection scenarios discussed in the literature: a) anti-parallel reconnection and b) component reconnection. Early spacecraft observations were limited to the detection of accelerated ion beams in the magnetopause boundary layer to determine the general direction of the reconnection X-line location with respect to the spacecraft. An improved view of the reconnection location at the magnetopause evolved from ionospheric emissions observed by polar-orbiting imagers. These observations and the observations of accelerated ion beams revealed that both scenarios occur at the magnetopause. Improved methodology using the time-of-flight effect of precipitating ions in the cusp regions and the cutoff velocity of the precipitating and mirroring ion populations was used to pinpoint magnetopause reconnection locations for a wide range of solar wind conditions. The results from these methodologies have been used to construct an empirical reconnection X-line model known as the Maximum Magnetic Shear model. Since this model’s inception, several tests have confirmed its validity and have resulted in modifications to the model for certain solar wind conditions. This review article summarizes the observational evidence for the location of magnetic reconnection at the Earth’s magnetopause, emphasizing the properties and efficacy of the Maximum Magnetic Shear Model.

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Shadow monochromatic backlighting: Large-field high resolution X-ray shadowgraphy with improved spectral tunability

Laser and Particle Beams ◽

10.1017/s0263034601192189 ◽

2001 ◽

Vol 19 (2) ◽

pp. 285-293 ◽

Cited By ~ 25

Author(s):

T.A. PIKUZ ◽

A. YA. FAENOV ◽

M. FRAENKEL ◽

A. ZIGLER ◽

F. FLORA ◽

...

Keyword(s):

High Resolution ◽

High Spatial Resolution ◽

Field Of View ◽

Large Field ◽

X Ray ◽

Traditional Scheme ◽

Wide Range ◽

Wide Wavelength Range ◽

Bent Crystals ◽

First Time

The shadow monochromatic backlighting (SMB) scheme, a modification of the well-known soft X-ray monochromatic backlighting scheme, is proposed. It is based on a spherical crystal as the dispersive element and extends the traditional scheme by allowing one to work with a wide range of Bragg angles and thus in a wide spectral range. The advantages of the new scheme are demonstrated experimentally and supported numerically by ray-tracing simulations. In the experiments, the X-ray backlighter source is a laser-produced plasma, created by the interaction of an ultrashort pulse, Ti:Sapphire laser (120 fs, 3–5 mJ, 1016 W/cm2 on target) or a short wavelength XeCl laser (10 ns, 1–2 J, 1013 W/cm2 on target) with various solid targets (Dy, Ni + Cr, BaF2). In both experiments, the X-ray sources are well localized spatially (∼20 μm) and are spectrally tunable in a relatively wide wavelength range (λ = 8–15 Å). High quality monochromatic (δλ/λ ∼ 10−5–10−3) images with high spatial resolution (up to ∼4 μm) over a large field of view (a few square millimeters) were obtained. Utilization of spherically bent crystals to obtain high-resolution, large field, monochromatic images in a wide range of Bragg angles (35° < Θ < 90°) is demonstrated for the first time.

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Deep Radio Imaging with MERLIN of the Supernova Remnants in M82

International Astronomical Union Colloquium ◽

10.1017/s0252921100009234 ◽

2005 ◽

Vol 192 ◽

pp. 227-231

Author(s):

T.W.B. Muxlow ◽

A. Pedlar ◽

J.D. Riley ◽

A.R. McDonald ◽

R.J. Beswick ◽

...

Keyword(s):

High Resolution ◽

Supernova Remnants ◽

Shell Structures ◽

Starburst Galaxy ◽

Radio Structure ◽

High Resolution Image ◽

Radio Imaging ◽

Wide Range ◽

Deep Integration ◽

First Time

SummaryAn 8 day MERLIN deep integration at 5GHz of the central region of the starburst galaxy M82 has been used to investigate the radio structure of a number of supernova remnants in unprecedented detail revealing new shells and partial shell structures for the first time. In addition, by comparing the new deep 2002 image with an astrometrically aligned image from 36 hours of data taken in 1992, it has been possible to directly measure the expansion velocities of 4 of the most compact remnants in M82. For the two most compact remnants, 41.95+575 and 43.31+592, expansion velocities of 2800 ± 300 km s-1 and 8750 ± 400kms-1have been derived. These confirm and refine the measured expansion velocities which have been derived from VLBI multi-epoch studies. For remnants 43.18+583 and 44.01+596, expansion velocities of 10500 ± 750km s-1 and 2400 ± 250 kms-1have been measured for the first time. In addition, the peak of the radio emission for SNR 45.17+612 has moved between the two epochs implying velocities around 7500km s-1. The relatively compact remnants in M82 are thus found to be expanding over a wide range of velocities which appear unrelated to their size. The new 2002 map is the most sensitive high-resolution image yet made of M82, achieving an rms noise level of 17μJy beam-1. This establishes a first epoch for subsequent deep studies of expansion velocities for many SNR within M82.

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Electric vehicle charging stations in the workplace with high-resolution data from casual and habitual users

Scientific Data ◽

10.1038/s41597-021-00956-1 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Omar Isaac Asensio ◽

M. Cade Lawson ◽

Camila Z. Apablaza

Keyword(s):

High Resolution ◽

Real Time ◽

Electric Vehicle ◽

Optimal Power Flow ◽

Service Providers ◽

High Temporal Resolution ◽

High Resolution Data ◽

Demand Models ◽

Charging Stations ◽

Resolution Data

AbstractProblems of poor network interoperability in electric vehicle (EV) infrastructure, where data about real-time usage or consumption is not easily shared across service providers, has plagued the widespread analysis of energy used for transportation. In this article, we present a high-resolution dataset of real-time EV charging transactions resolved to the nearest second over a one-year period at a multi-site corporate campus. This includes 105 charging stations across 25 different facilities operated by a single firm in the U.S. Department of Energy Workplace Charging Challenge. The high-resolution data has 3,395 real-time transactions and 85 users with both paid and free sessions. The data has been expanded for re-use such as identifying charging behaviour and segmenting user groups by frequency of usage, stage of adoption, and employee type. Potential applications include but are not limited to simulating and parameterizing energy demand models; investigating flexible charge scheduling and optimal power flow problems; characterizing transportation emissions and electric mobility patterns at high temporal resolution; and evaluating characteristics of early adopters and lead user innovation.

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Comparison of analytical methods used for measuring major ions in the EPICA Dome C (Antarctica) ice core

Annals of Glaciology ◽

10.3189/172756402781817022 ◽

2002 ◽

Vol 35 ◽

pp. 299-305 ◽

Cited By ~ 34

Author(s):

Geneviève C. Littot ◽

Robert Mulvaney ◽

Regine Röthlisberger ◽

Roberto Udisti ◽

Eric W. Wolff ◽

...

Keyword(s):

High Resolution ◽

Ion Chromatography ◽

Major Ions ◽

Full Range ◽

Ice Core ◽

Flow Analysis ◽

Ice Cores ◽

High Resolution Data ◽

Wide Range

AbstractIn the past, ionic analyses of deep ice cores tended to consist of a few widely spaced measurements that indicated general trends in concentration. the ion-chromatographic methods widely used provide well-validated individual data, but are time-consuming. the development of continuous flow analysis (CFA) methods has allowed very rapid, high-resolution data to be collected in the field for a wide range of ions. In the European Project for Ice Coring in Antarctica (EPICA) deep ice-core drilling at Dome C, many ions have been measured at high resolution, and several have been analyzed by more than one method. the full range of ions has been measured in five different laboratories by ion chromatography (IC), at resolutions of 2.5–10 cm. In the field, CFA was used to measure the ions Na+, Ca2+, nitrate and ammonium. Additionally, a new semi-continuous in situ IC method, fast ion chromatography (FIC), was used to analyze sulphate, nitrate and chloride. Some data are now available to 788 m depth. In this paper we compare the data obtained by the three methods, and show that the rapid methods (CFA and FIC) give an excellent indication of trends in ionic data. Differences between the data from the different methods do occur, and in some cases these are genuine, being due to differences in speciation in the methods. We conclude that the best system for most deep ice-core analysis is a rapid system of CFA and FIC, along with in situ meltwater collection for analysis of other ions by IC, but that material should be kept aside for a regular check on analytical quality and for more detailed analysis of some sections.

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Technical note: Improving the AWAT filter with interpolation schemes for advanced processing of high resolution data

10.5194/hess-2016-51 ◽

2016 ◽

Author(s):

Andre Peters ◽

Thomas Nehls ◽

Gerd Wessolek

Keyword(s):

High Resolution ◽

Spline Interpolation ◽

Selection Criterion ◽

Adaptive Threshold ◽

Technical Note ◽

Measuring System ◽

High Temporal Resolution ◽

Data Set ◽

High Resolution Data ◽

Linear Scheme

Abstract. Weighing lysimeters with appropriate data filtering yield the most precise and unbiased information for precipitation (P) and evapotranspiration (ET). A recently introduced filter scheme for such data is the AWAT (Adaptive Window and Adaptive Threshold) filter [Peters, A., Nehls, T., Schonsky, H., and Wessolek, G.: Separating precipitation and evapotranspiration from noise – a new filter routine for high-resolution lysimeter data, Hydrol. Earth Syst. Sci., 18, 1189–1198, doi:10.5194/hess-18-1189-2014, 2014]. The filter applies an adaptive threshold to separate significant from insignificant mass changes, guaranteeing that P and ET are not overestimated, and uses a step interpolation between the significant mass changes. In this contribution we show that the step interpolation scheme, which reflects the resolution of the measuring system, can lead to unrealistic prediction of P and ET, especially if they are required in high temporal resolution. We introduce linear and spline interpolation schemes to overcome these problems. To guarantee that medium to strong precipitation events abruptly following low or zero fluxes are not smoothed in an unfavourable way, a simple heuristic selection criterion is used, which attributes such precipitations to the step interpolation. The three interpolation schemes (step, linear and spline) are tested and compared using a data set from a grass-reference lysimeter with one minute resolution, ranging from 1 January to 5 August 2014. The selected output resolutions for P and ET prediction are one day, one hour and 10 minutes. As expected, the step scheme yielded reasonable flux rates only for a resolution of one day, whereas the other two schemes are well able to yield reasonable results for any resolution. The spline scheme returned slightly better results than the linear scheme concerning the differences between filtered values and raw data. Moreover, this scheme allows continuous differentiability of filtered data so that any output resolution for the fluxes is sound. Since computational burden is not problematic for any of the interpolation schemes, we suggest to use always the spline scheme.

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RADAR-base: An Open Source mHealth Platform for Collecting, Monitoring and Analyzing Data Using Sensors, Wearables, and Mobile Devices (Preprint)

10.2196/preprints.11734 ◽

2018 ◽

Cited By ~ 1

Author(s):

Yatharth Ranjan ◽

Zulqarnain Rashid ◽

Callum Stewart ◽

Maximilian Kerz ◽

Mark Begale ◽

...

Keyword(s):

High Resolution ◽

Data Collection ◽

Open Source ◽

User Interfaces ◽

Large Scale ◽

Streaming Data ◽

Security And Privacy ◽

Multiple Sources ◽

High Resolution Data ◽

Wide Range

BACKGROUND With a wide range of use cases in both research and clinical domains, collecting continuous mobile health (mHealth) streaming data from multiple sources in a secure, highly scalable and extensible platform is of high interest to the open source mHealth community. The EU IMI RADAR-CNS program is an exemplar project with the requirements to support collection of high resolution data at scale; as such, the RADAR-base platform is designed to meet these needs and additionally facilitate a new generation of mHealth projects in this nascent field. OBJECTIVE Wide-bandwidth networks, smartphone penetrance and wearable sensors offer new possibilities for collecting (near) real-time high resolution datasets from large numbers of participants. We aimed to build a platform that would cater for large scale data collection for remote monitoring initiatives. Key criteria are around scalability, extensibility, security and privacy. METHODS RADAR-base is developed as a modular application, the backend is built on a backbone of the highly successful Confluent/Apache Kafka framework for streaming data. To facilitate scaling and ease of deployment, we use Docker containers to package the components of the platform. RADAR-base provides two main mobile apps for data collection, a Passive App and an Active App. Other 3rd Party Apps and sensors are easily integrated into the platform. Management user interfaces to support data collection and enrolment are also provided. RESULTS General principles of the platform components and design of RADAR-base are presented here, with examples of the types of data currently being collected from devices used in RADAR-CNS projects: Multiple Sclerosis, Epilepsy and Depression cohorts. CONCLUSIONS RADAR-base is a fully functional, remote data collection platform built around Confluent/Apache Kafka and provides off-the-shelf components for projects interested in collecting mHealth datasets at scale.

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Evaluating GRACE Mass Change Time Series for the Antarctic and Greenland Ice Sheet—Methods and Results

Geosciences ◽

10.3390/geosciences9100415 ◽

2019 ◽

Vol 9 (10) ◽

pp. 415 ◽

Cited By ~ 6

Author(s):

Andreas Groh ◽

Martin Horwath ◽

Alexander Horvath ◽

Rakia Meister ◽

Louise Sandberg Sørensen ◽

...

Keyword(s):

Synthetic Data ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Data Sets ◽

Drainage Basins ◽

Time Period ◽

Wide Range ◽

Gravity Recovery ◽

The Antarctic ◽

First Time

Satellite gravimetry data acquired by the Gravity Recovery and Climate Experiment (GRACE) allows to derive the temporal evolution in ice mass for both the Antarctic Ice Sheet (AIS) and the Greenland Ice Sheet (GIS). Various algorithms have been used in a wide range of studies to generate Gravimetric Mass Balance (GMB) products. Results from different studies may be affected by substantial differences in the processing, including the applied algorithm, the utilised background models and the time period under consideration. This study gives a detailed description of an assessment of the performance of GMB algorithms using actual GRACE monthly solutions for a prescribed period as well as synthetic data sets. The inter-comparison exercise was conducted in the scope of the European Space Agency’s Climate Change Initiative (CCI) project for the AIS and GIS, and was, for the first time, open to everyone. GMB products generated by different groups could be evaluated and directly compared against each other. For the period from 2003-02 to 2013-12, estimated linear trends in ice mass vary between −99 Gt/yr and −108 Gt/yr for the AIS and between −252 Gt/yr and −274 Gt/yr for the GIS, respectively. The spread between the solutions is larger if smaller drainage basins or gridded GMB products are considered. Finally, findings from the exercise formed the basis to select the algorithms used for the GMB product generation within the AIS and GIS CCI project.

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Capturing Complexity

Advances in Archaeological Practice ◽

10.7183/2326-3768.2.3.147 ◽

2014 ◽

Vol 2 (3) ◽

pp. 147-163 ◽

Cited By ~ 9

Author(s):

Steven A. Wernke ◽

Julie A. Adams ◽

Eli R. Hooten

Keyword(s):

High Resolution ◽

Software Systems ◽

High Resolution Data ◽

Mobile Gis ◽

Colonial Peru ◽

Data Registry ◽

Wide Range ◽

Close Range ◽

A Site ◽

Gis Software

AbstractMedium-scale archaeological phenomena (large settlements, landscape features and infrastructural systems, road networks, etc.) pose significant challenges to archaeological documentation. Traditionally, such features are mapped either schematically or via labor-intensive (or otherwise costly) high-resolution methods. The advent of inexpensive, packable unmanned aerial vehicles (UAVs) and lighter-than-air platforms, combined with increasingly sophisticated photogrammetric and mobile geographic information system (GIS) software systems, presents opportunities for improving on these compromises. Here, we present results from test flights and photogrammetric mapping using UAVs and a meteorological balloon, combined with mobile GIS-based attribute registry of architectonic features at a large, complex colonial planned settlement (Mawchu Llacta de Tuti) in highland colonial Peru. First, the operating parameters of UAVs are presented, as well as the imagery capture and photogrammetric processing work flows. Second, we provide an overview of the tablet-based mobile GIS system used to digitize a site plan (based on the imagery from the UAV) and register architectural attributes from each building. The results from initial testing suggest that in the near future, such combined close-range photogrammetry and mobile GIS-based systems will significantly enhance and expedite high-resolution data registry of a wide range of archaeological features, sites, and landscapes.

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Asymmetries in the Earth's dayside magnetosheath: results from global hybrid-Vlasov simulations

Annales Geophysicae ◽

10.5194/angeo-38-1045-2020 ◽

2020 ◽

Vol 38 (5) ◽

pp. 1045-1062

Author(s):

Lucile Turc ◽

Vertti Tarvus ◽

Andrew P. Dimmock ◽

Markus Battarbee ◽

Urs Ganse ◽

...

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Mach Number ◽

Bow Shock ◽

Strong Impact ◽

Large Variability ◽

Parker Spiral ◽

Wide Range ◽

First Time ◽

Single Set

Abstract. Bounded by the bow shock and the magnetopause, the magnetosheath forms the interface between solar wind and magnetospheric plasmas and regulates solar wind–magnetosphere coupling. Previous works have revealed pronounced dawn–dusk asymmetries in the magnetosheath properties. The dependence of these asymmetries on the upstream parameters remains however largely unknown. One of the main sources of these asymmetries is the bow shock configuration, which is typically quasi-parallel on the dawn side and quasi-perpendicular on the dusk side of the terrestrial magnetosheath because of the Parker spiral orientation of the interplanetary magnetic field (IMF) at Earth. Most of these previous studies rely on collections of spacecraft measurements associated with a wide range of upstream conditions which are processed in order to obtain average values of the magnetosheath parameters. In this work, we use a different approach and quantify the magnetosheath asymmetries in global hybrid-Vlasov simulations performed with the Vlasiator model. We concentrate on three parameters: the magnetic field strength, the plasma density, and the flow velocity. We find that the Vlasiator model reproduces the polarity of the asymmetries accurately but that their level tends to be higher than in spacecraft measurements, probably because the magnetosheath parameters are obtained from a single set of upstream conditions in the simulation, making the asymmetries more prominent. A set of three runs with different upstream conditions allows us to investigate for the first time how the asymmetries change when the angle between the IMF and the Sun–Earth line is reduced and when the Alfvén Mach number decreases. We find that a more radial IMF results in a stronger magnetic field asymmetry and a larger variability of the magnetosheath density. In contrast, a lower Alfvén Mach number leads to a reduced magnetic field asymmetry and a decrease in the variability of the magnetosheath density, the latter likely due to weaker foreshock processes. Our results highlight the strong impact of the quasi-parallel shock and its associated foreshock on global magnetosheath properties, in particular on the magnetosheath density, which is extremely sensitive to transient quasi-parallel shock processes, even with the perfectly steady upstream conditions in our simulations. This could explain the large variability of the density asymmetry levels obtained from spacecraft measurements in previous studies.

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