Kinetic-scale Current Sheets in the Solar Wind at 1 au: Properties and the Necessary Condition for Reconnection

We present a data set and properties of 18,785 proton kinetic-scale current sheets collected over 124 days in the solar wind using magnetic field measurements at 1/11 s resolution aboard the Wind spacecraft. We show that all of the current sheets are in the parameter range where reconnection is not suppressed by diamagnetic drift of the X-line. We argue this necessary condition for magnetic reconnection is automatically satisfied due to the geometry of current sheets dictated by their source, which is the local plasma turbulence. The current sheets are shown to be elongated along the background magnetic field and dependence of the current sheet geometry on local plasma beta is revealed. We conclude that reconnection in the solar wind is not likely to be suppressed or controlled by the diamagnetic suppression condition.

Experimental Study of the Velocity of the Electrovortex Flow of In-Ga-Sn in Hemispherical Geometry

The paper describes the application of the thermocorrelation method for measuring the velocity in a current-carrying liquid. An electrovortex flow occurs when the current passing through a conducting medium interacts with its own magnetic field. Measurements of the velocity of the turbulent electrovortex flow of the liquid metal (eutectic alloy In-Ga-Sn) were carried out in a hemispherical container in the range of currents of 100–450 amperes in the presence and absence of compensation of the Earth’s magnetic field. The efficiency of the thermocorrelation method in a current-carrying liquid has been demonstrated. The dependences of the axial velocity on the current and the velocity profiles along the axis were obtained. It was found that the presence of the Earth’s magnetic field leads to a significant decrease in the average value of the axial velocity in the entire range of currents.

Are the Hessdalen Lights a Reality, an Illusion, or a Mix of the Two ?

The Hessdalen lights (HLs in the following) are luminous, floating, more or less spherical atmospheric phenomena, with a lifetime of a few seconds to sometimes several minutes. These phenomena are seen in the Hessdalen Valley in Norway for decades. Unfortunately a full understanding of these baffling events is still lacking in spite of solid working scientific projects intended to explain them. This paper tries to improve the situation. It raises the questions where the energy for the creation of the HLs comes from, and what was its nature : (geo) chemical, electric or still other ? We propose a new scenario for the Hessdalen lights. It exploits the recent idea of stable and traversable wormholes whose the potential existence is beginning to be recognized in physics. Even though appearing highly speculative, this hypothesis has not been so far explored elsewhere while it could supply a full description of the wholeness of the phenomenon. On the other side even if the probability that a HL could indeed be a wormhole is may be low, this question should not dismissed out of hand. These theoretical considerations could help to increase knowledge and understanding of both the HLs and the wormholes, drawing mutual enrichment. In other words HLs could betray the presence of hidden wormholes and we must not let slip through our fingers this possibility even if it is very tiny. In this framework we discuss of the stability, the energetics and the oversized dimension of the HLs. In physics the final arbiter is not the theory but the experiment. Thus some “simple” experiments are eventually suggested (high time resolution photometry and magnetic field measurements). Eventually, if the process described is real and after mastering it, there is a free and inexhaustible source of energy that would be derived, a tremendous breakthrough after which we could forget the controlled nuclear fusion. Regarding its structure, the paper is divided in four paragraphs 1, 2,3, 4 independent of each other. Illustrative pictures help to understand the text.

An Innovative Low Cost Well Monitoring Solution: W.A.N.D

Wireless Autonomous Nano-sensor Device (WAND) system is a disruptive cost-effective micro-system for well monitoring. It allows to realize pressure, temperature, inertial, and magnetic field measurements in harsh conditions; it also offers Bluetooth low-power communication and Wireless charging capabilities. Analysis’ results of an industrial offshore pilot realized in Congo (a world first in O&G industry in such complex environment), and major improvements implemented after this pilot are reported in this paper. Accomplished advancements comprise hardware and software developments extending operation lifetime, and simplifying on-site utilization. To date, there is not a commercial solution of this type in the market, the realization of this project is a real innovation allowing practical and low-cost monitoring during well intervention while minimizing the risks associated with standard Rigless intervention. Other applications regarding dry-tree wells on tension-leg platforms (TLP), drilling and completion operations, and pipeline monitoring are being investigated, too.

The fluxgate magnetometer of the Low Orbit Pearl Satellites (LOPS): overview of in-flight performance and initial results

The Low Orbit Pearl Satellite series consists of six constellations, with each constellation consisting of three identical microsatellites that line up just like a string of pearls. The first constellation of three satellites were launched on 29 September 2017, with an inclination of ∼ 35.5∘ and ∼ 600 km altitude. Each satellite is equipped with three identical fluxgate magnetometers that measure the in situ magnetic field and its low-frequency fluctuations in the Earth's low-altitude orbit. The triple sensor configuration enables separation of stray field effects generated by the spacecraft from the ambient magnetic field (e.g., Zhang et al., 2006). This paper gives a general description of the magnetometer including the instrument design, calibration before launch, in-flight calibration, in-flight performance, and initial results. Unprecedented spatial coverage resolution of the magnetic field measurements allow for the investigation of the dynamic processes and electric currents of the ionosphere and magnetosphere, especially for the ring current and equatorial electrojet during both quiet geomagnetic conditions and storms. Magnetic field measurements from LOPS could be important for studying the method to separate their contributions of the Magnetosphere-Ionosphere (M-I) current system.

Evaluating the Accuracy of Magnetospheric Magnetic Field Models Using Cluster Spacecraft Magnetic Field Measurements

Magnetic fields in the inner magnetosphere can be obtained as vector sums of the Earth’s own internal magnetic field and magnetic fields stemming from currents flowing in the space plasma. While the Earth’s internal magnetic field is accurately described by the International Geomagnetic Reference Field (IGRF) model, the characterization of the external magnetic fields is significantly more complicated, as they are highly variable and dependent on the actual level of the geomagnetic activity. Tsyganenko family magnetic field models (T89, T96, T01, TA15B, TA15N), parameterized by the geomagnetic activity level and solar wind parameters, are often used by the involved community to describe these fields. In the present paper, we use a large dataset (2001–2018) of magnetospheric magnetic field measurements obtained by the four Cluster spacecraft to assess the accuracy of these models. We show that, while the newer models (T01, TA15B, TA15N) perform significantly better than the old ones (T89, T96), there remain some systematic deviations, in particular at larger latitudes. Moreover, we compare the locations of the min-B equator determined using the four-point Cluster spacecraft measurements with the locations determined using the magnetic field models. We demonstrate that, despite the newer models being comparatively slightly more accurate, an uncertainty of about one degree in the latitude of the min-B equator remains.