Spiral Orientation Research Articles

Пьезоэлектрический дисковый актюатор кручения с дискретно-спиральными электродами

A mathematical model of a disk (ring) torsion actuator with curvilinear interdigital electrodes – «villi» of a spiral form, which are characterized by a constant value of the orientation angle of an arbitrary section of the villus to the circumferential direction of the disk, has been developed. Bases of electrode-villi interacting with each other through local areas of piezoelectric layer are connected with periodic alternation to central or peripheral concentric circular base electrodes, to outputs of which control voltages are connected. As a result of numerical modeling of the «twisting bimorph» graphs of the dependence of the twist angle and the blocking torque on the ratio of the inner and outer radii and the values of the control voltage at the outputs of the base electrodes of the annular two-layer actuator with symmetrical (relative to the radial line) directions of the spiral orientations of the electrode-villi and, as a result, the spiral polarization lines of the piezoelectric layers working for tension/compression.

Numerical analysis of polyethylene based nano-enhanced phase change material in cylindrical storage system

Environmental sustainability encompasses various dimensions like waste management, energy conservation, and environmental impact. The use of waste plastic; Linear Low-density polyethylene (LLDPE) as a phase change material (PCM) offers a sustainable solution for energy and the environment. This study investigates LLDPE/ functionalize graphene composites for latent heat storage using a shell and helical coil for effective energy conversion. The simulation is carried out for constant flux and constant temperature heat supply to understand the influence of nano additives and geometrical parameters such as spiral coil diameter (Dc ), pitch (Pc ), and orientation of storage unit (θ). The result reveals that nano additive influence effectively and reduces the charging time approximately from 20 to 40% for 1–5% of nano-addition. Simulation results reveals that the spiral coil diameter is crucial for melting and heat transmission. The overall melting time is decreased by up to 56% by increasing the spiral coil diameter from 21 to 49 mm for LLDPE while the effect of pitch length variation is found not significant. The constant temperature heating at 160, 250 and 340°C gives effective results for charging time improvement. The geometrical orientations from 0 to 90 degrees report that the horizontal position is the best orientation for energy storage.

Formation and development of lamellar histoarchitecture of the ventricular myocardium of chick embryos

Background. The existence of several models of the myolamellar structure of the ventricular myocardium, which currently has a number of contradictory provisions, reflects the need for a reasonable integration of the results of different methods. Under these circumstances, the study of those ontogenetic mechanisms that are responsible for the formation and development of the myolamellar architecture of the myocardium is of great interest. The purpose of the study is to determine the ontogenetic transformations of the embryonic chicken heart that ensure the formation and development of the myolamellar structure of the ventricular myocardium. Methods. The work examined the embryos of Cobb500 cross chickens from the beginning of the 10th day to the 21st day of incubation. The lamellar organization of the ventricular myocardium was studied using light and transmission electron microscopy. Results. Starting from the 36th stage according to NN (the beginning of the 10th day of incubation), the active development of the stromal component was observed in the heart of chicken embryos, which led to the division of the tissue of the compact ventricular myocardium into groups of muscle fibers in the form of narrow elongated flat plates containing thicker than 3 to 5 rows of cardiomyocytes. At the 41st and 43rd stages of development, active development of the intercellular matrix and division of the myocardium mass into muscle plates continued as part of the compact ventricular myocardium. The intercellular spaces within the plates narrowed, and between the myolamellae, the perimysium accumulated elements of the microcirculatory bed, functionally active fibroblasts, a large amount of amorphous substance, and bundles of formed collagen fibers. At the final stages of embryogenesis, the muscle plates of the left ventricle acquired a pronounced spiral orientation with a gradual displacement of the long axis of the muscle fibers in the direction from the apex of the ventricle to its base. In the wall of the right ventricle, the location of the myolamella acquired a transverse oblique-circular orientation. Conclusion. A comparison of the structure and geometry of the myolamella made it possible to reveal that starting from the 38th stage of development in the left ventricle, the conditions for the translational-rotational mechanism of chamber contraction were formed and increased, in which the formation of the difference between the systolic and diastolic volumes of the left ventricle is ensured not only by the longitudinal apico-basal vector compression of the cavity, but also by mutual sliding of spirally oriented plates in the ventricular wall. In right ventricle, the contraction mechanism is based on the longitudinal-circular compression of the chamber in accordance with the oblique-circular orientation of the muscle fibers in the composition of the myolamella without displacement in the state of systole.

Correlation Between Corneal Whorl-Like Nerve and Retinal Neurodegenerative Changes and Their Association With Microvessel Perfusion in Diabetes.

The purpose of this study was to compare the evolution of changes in the corneal nerves, retinal nerves, and cells and blood vessels at a single time point in early diabetic retinopathy (DR). Eighty participants (60 with diabetes and 20 nondiabetic controls) were examined. DR was graded according to the International Classification of Diabetic Retinopathy. Inferior whorl length (IWL), spiral orientation, central nerve fiber length (CNFL), retinal nerve fiber layer (RNFL) thickness, ganglion cell complex (GCC) layer thickness, global loss volume (GLV), focal loss volume (FLV) indices, superficial (sVD), and deep vessel densities (dVD) were examined. Compared with those of healthy controls, the IWL, CNFL, and FLV were decreased in the diabetic groups (P < 0.001). The IWL was significantly positively correlated with the RNFL and GCC thicknesses in the diabetic group (r = 0.248, P = 0.006 and r = 0.207, P = 0.023, respectively) and significantly negatively correlated with the FLV (r = -0.535, P < 0.001). The sVD was significantly positively correlated with the RNFL thickness (r = 0.314, P < 0.001) and negatively correlated with the GLV (r = -0.229, P = 0.012). Our findings suggest a correlation between corneal whorl-like nerve plexus and retinal nerve changes in the early stages of DR and that the IWL of the cornea may be able to indicate the extent of DR. Retinal nerve changes are associated with retinal microvessel perfusion, and nerve changes may precede vessel lesions.

Magneto-responsive optics in a chiral crystal with thermally triggered reversible phase transitions between chiral space groups.

Herein, a chiral charge transfer crystal that exhibits reversible phase transition between chiral space groups has been fabricated. When the phase switches from left-handed to right-handed chiral space group, more pronounced orbital angular momentum effects will be generated, where magneto-responsive optics are the opposite for chiral enantiomers. Moreover, circularly polarized light could enhance the chiral orbit of the crystal with the same spiral orientation to let spin have a better ability to resist external magnetic field. Thus, the magnetic field dependence of transmission and photoluminescence of chiral crystals are strongly dependent on the polarized state of incident light. Furthermore, by studying the coupling among spin, orbit, and circular photon, we obtained that the chiral orbit plays a key role in the coupling between the spin and circular photon. It is expected that this work could promote further exploration of organic chiral magneto-optical crystals in potential applications of sensing.

Influence of spiral topographies on human limbal-derived immortalized corneal epithelial cells.

Cells migrate from the limbus to the corneal epithelium following a centripetal pathway. Corneal epithelial cells tend to orientate in spiral or vortex patterns. However, when cultured in-vitro, limbal derived corneal epithelia do not tend to align or migrate in a spiral pattern. Here, we used soft lithography to create silk fibroin substrates with spiral topographies that direct the human limbal-derived immortalized corneal epithelial cells (hTCEpi) to form a spiral orientation. The impact of this topography on the cells was then characterized. The spiral patterns affected cytoskeletal organization, cell spreading, and nuclei shapes. Spiral width and numbers had a significant impact on proliferation of cells, their focal adhesion, their chromatin condensation, and number of actin filaments. Immunocytochemical staining showed that the spiral pattern enhanced the expression of markers associated with limbal stem cells. The current work illustrates micro spiral patterns can serve to control the nature of limbal derived epithelial cells by providing relevant biophysical cues.

Wear Mechanisms and Performance of PET Shredder Blade with Various Geometries and Orientations

Shredder blade is the main component of a shredder machine used in plastic recycling. A comparative performance study was conducted on the shredder blade with different geometries and orientations to understand its wear and shredding mechanism. Identification of the loading distribution along the shredder blades was observed in different orientations. The microstructure and hardness of the worn cutting edge and as-received shredder blade were characterised by optical microscopy, scanning electron microscopy along with the energy dispersive X-ray, X-ray diffraction analysis and hardness testing. The wear mechanism in the shredder blades was categorised as progressive wear. The progressive wear was due to the abrasive, adhesive, and oxidation wear. Recycling efficiency, shredding efficiency, and percentage retention are the parameters used to evaluate the performance of the machine with various geometries and orientations. The best combination of the geometry and orientation is the double-edge shredder blade with spiral orientation, which exhibited recycling efficiency at 97.39 ± 0.04%, shredding efficiency at 69.53 ± 1.32%, and retention at 2.61 ± 0.04%, along with a smaller number of blades recorded severe wear.

Adopting Scenario-Based approach to solve optimal reactive power Dispatch problem with integration of wind and solar energy using improved Marine predator algorithm

The penetration of renewable energy resources into electric power networks has been increased considerably to reduce the dependence of conventional energy resources, reducing the generation cost and greenhouse emissions. The wind and photovoltaic (PV) based systems are the most applied technologies in electrical systems compared to other technologies of renewable energy resources. However, there are some complications and challenges to incorporating these resources due to their stochastic nature, intermittency, and variability of output powers. Therefore, solving the optimal reactive power dispatch (ORPD) problem with considering the uncertainties of renewable energy resources is a challenging task. Application of the Marine Predators Algorithm (MPA) for solving complex multimodal and non-linear problems such as ORPD under system uncertainties may cause entrapment into local optima and suffer from stagnation. The aim of this paper is to solve the ORPD problem under deterministic and probabilistic states of the system using an improved marine predator algorithm (IMPA). The IMPA is based on enhancing the exploitation phase of the conventional MPA. The proposed enhancement is based on updating the locations of the populations in spiral orientation around the sorted populations in the first iteration process, while in the final stage, the locations of the populations are updated their locations in adaptive steps closed to the best population only. The scenario-based approach is utilized for uncertainties representation where a set of scenarios are generated with the combination of uncertainties the load demands and power of the renewable resources. The proposed algorithm is validated and tested on the IEEE 30-bus system as well as the captured results are compared with those outcomes from the state-of-the-art algorithms. A computational study shows the superiority of the proposed algorithm over the other reported algorithms.

Weak ferromagnetism linked to the high-temperature spiral phase of YBaCuFeO5

The layered perovskite ${\mathrm{YBaCuFeO}}_{5}$ is a rare example of a cycloidal spiral magnet whose ordering temperature ${T}_{\text{spiral}}$ can be tuned far beyond room temperature by adjusting the degree of ${\mathrm{Cu}}^{2+}/{\mathrm{Fe}}^{3+}$ chemical disorder in the structure. This unusual property qualifies this material as one of the most promising spin-driven multiferroic candidates. However, very little is known about the response of the spiral to magnetic fields, crucial for magnetoelectric cross-control applications. Using bulk magnetization and neutron powder diffraction measurements under magnetic fields up to 9 T, we report here a temperature-magnetic field phase diagram of this material. Besides revealing a strong stability of the spiral state, our data uncover the presence of weak ferromagnetism coexisting with the spiral modulation. Since ferromagnets can be easily manipulated with magnetic fields, this observation opens new perspectives for the control of the spiral orientation, directly linked to the polarization direction, as well as for a possible future use of this material in technological applications.

Magnetoelectric phenomena in Fe langasites

Experimental and theoretical studies of the magnetoelectric properties of a series of Fe langasite multiferroics (${\mathrm{Ba}}_{3}{\mathrm{NbFe}}_{3}{\mathrm{Si}}_{2}{\mathrm{O}}_{14}, {\mathrm{Ba}}_{3}{\mathrm{TaFe}}_{3}{\mathrm{Si}}_{2}{\mathrm{O}}_{14}$, and ${\mathrm{Sr}}_{3}{\mathrm{TaFe}}_{3}{\mathrm{Si}}_{2}{\mathrm{O}}_{14}$) with planar triangular spiral magnetic structure and double chiral magnetic order have been carried out. Magnetic field induced electric polarization is observed to emerge in the basal $a{b}^{*}$ plane of the trigonal crystal, depending on both the magnitude (up to 60 T) and orientation of the magnetic field. Remarkably, the induced polarization is very sensitive to the projection of the field onto the $c$ axis, with a sharp increase in polarization found for small deviations of the field from the basal plane and the sign of polarization determined by the direction of the field deviation. At high magnetic fields, the electric polarization behavior changes qualitatively and strongly depends on the magnetic field orientation. A detailed group theoretical analysis of the magnetic and magnetoelectric properties of Fe langasites is presented, and a relationship between the polarization and magnetic order parameters in an external magnetic field is established. We show that, in a magnetic field, the spiral magnetic structure is rotated and canted with respect to the original structure under zero field. The competition between these two processes, rotation and canting, strongly depends on the magnetic field orientation, and determines the polarization behavior. We propose a simplified description of the Fe langasites' triangular spiral magnetic structure at low temperatures and with saturated moments, characterized by the spiral plane orientation and the field-induced magnetization only. We establish that, at weak fields, the appearance of polarization occurs mainly due to the reorientation of the magnetic spiral (analogous to a spin-flop transition) and could be explained by the inverse Dzyaloshinskii-Moriya interaction. At high fields (above 8 T), the polarization change occurs via canting of the magnetic spiral, owing to Fe-Fe exchange and single-ion contributions.

Super-aligned carbon nanotubes and GelMA hydrogel composite scaffolds promote spiral ganglion neuron growth and orientation

Sensorineural hearing loss caused by the damage and degeneration of spiral ganglion neurons (SGNs) is a common disease. So, the regeneration and directional growth of spiral ganglion neurons (SGNs) is vital for the treatment of sensorineural hearing loss. In this study, we combined methacrylated gelatin (GelMA) hydrogel and super-aligned carbon nanotubes sheets (SACNTs) to form a composite material (GelMA-SACNT) that combined the good biocompatibility of GelMA hydrogel with the conductivity of carbon nanotubes. The prepared composite material retained the topological structure of SACNTs and thus provided a suitable platform for neural cell culture. SGNs grown on GelMA-SACNT showed well orientation, increased length of neurites and filopodia and increased area of the axon growth cone. Furthermore, neural network activity on the GelMA-SACNT was increased. These results clearly show that the prepared GelMA-SACNT can promote the growth of SGNs and the formation of anisotropic neural networks and thus has potential for the treatment of sensorineural hearing loss.

Structures of the human LONP1 protease reveal regulatory steps involved in protease activation

The human mitochondrial AAA+ protein LONP1 is a critical quality control protease involved in regulating diverse aspects of mitochondrial biology including proteostasis, electron transport chain activity, and mitochondrial transcription. As such, genetic or aging-associated imbalances in LONP1 activity are implicated in pathologic mitochondrial dysfunction associated with numerous human diseases. Despite this importance, the molecular basis for LONP1-dependent proteolytic activity remains poorly defined. Here, we solved cryo-electron microscopy structures of human LONP1 to reveal the underlying molecular mechanisms governing substrate proteolysis. We show that, like bacterial Lon, human LONP1 adopts both an open and closed spiral staircase orientation dictated by the presence of substrate and nucleotide. Unlike bacterial Lon, human LONP1 contains a second spiral staircase within its ATPase domain that engages substrate as it is translocated toward the proteolytic chamber. Intriguingly, and in contrast to its bacterial ortholog, substrate binding within the central ATPase channel of LONP1 alone is insufficient to induce the activated conformation of the protease domains. To successfully induce the active protease conformation in substrate-bound LONP1, substrate binding within the protease active site is necessary, which we demonstrate by adding bortezomib, a peptidomimetic active site inhibitor of LONP1. These results suggest LONP1 can decouple ATPase and protease activities depending on whether AAA+ or both AAA+ and protease domains bind substrate. Importantly, our structures provide a molecular framework to define the critical importance of LONP1 in regulating mitochondrial proteostasis in health and disease.

A Novel Modified Lightning Attachment Procedure Optimization Technique for Optimal Allocation of the FACTS Devices in Power Systems

The Flexible AC Transmission Systems (FACTS) are the static power electronic devices that are installed and used in AC transmission networks to enhance the capability of transferring the power for providing the controllability and stability. However, the optimization of site and size of these devices is a crucial task due to their high capital cost and practical capabilities. In this paper, the optimal reactive power dispatch (ORPD) embedded with two effective controllers including the Static VAR Compensator (SVC) and Thyristor Control Series Capacitor (TCSC) is solved using a Modified Lightning Attachment Procedure Optimizer (MLAPO). The searching capability of basic LAPO is enhanced and the stagnation of basic LAPO is avoided by application of levy flight distribution and spiral orientation motion. The optimization for these devices is for reducing the power losses, voltage deviations, and the operating cost. MLAPO is examined and tested on modified IEEE30 and IEEE57 bus-standards considering SVC and TCSC. The effectiveness of MLAPO is further analyzed and compared with the outcomes of the well-known optimization techniques namely LAPO, PSO, ALO, EO, MPA, WOA and SCA with and without FACTS devices.

Stochastic Optimal Planning of Distribution System Considering Integrated Photovoltaic-Based DG and DSTATCOM Under Uncertainties of Loads and Solar Irradiance

Optimal planning of integration the Photovoltage Distributed Generation (PV-DG) and DSTATCOM is a crucial task due to the stochastic variations of PV output power and the load demand which are related to solar irradiance variations and the activities of the customers, respectively. In this article, the optimal planning problem of the PV-DG and DSTATCOM system is solved. The proposed model considers the uncertainties of the solar irradiance and the load demand for a multi-objective function, including the cost reduction, the voltage profile, and stability index improvement. Modified Ant Lion Optimizer (MALO) is proposed to enhance the basic ALO searching ability using two strategies. The first strategy is based on Levy Flight Distribution (LFD) to strengthen the exploration of the algorithm and avoid the premature of the basic ALO. In contrast, the second strategy is based on updating the solutions in a spiral orientation to improve the exploitation of the algorithm. The IEEE 69-bus and 118-bus radial distribution systems are used to demonstrate the effectiveness of the proposed method, and the yielded simulations are compared with the basic ALO and other well-known optimization techniques for power loss minimization under deterministic conditions. The simulation results demonstrate that the techno-economic benefits can be increased considerably by optimal inclusion of two PV-DGs and DSTATCOMs compared with a single system.

How does PEDOT grow like nanoropes? A theoretical investigation in pace with experimental insights

Poly 3–4 ethylene dioxythiophene (PEDOT) is a highly conducting polymer insoluble and intractable when synthesized under normal synthesis conditions. This polymer was found to assume spiral or ropelike nanostructures with some modification in physical properties when grown in presence of a liquid crystal 5CB. The present work focuses on finding out the underlying reason behind the unique morphology of PEDOT theoretically, using density functional theory (DFT) as implemented in the Gaussian 03 suite of programs. From the energy minimized structures of 5CB clusters as well as PEDOT-5CB combinations it was observed that in the clusters of 6 or 10 molecules, 5CB is self-assembled in spiral orientation which might have guided the similar growth of PEDOT. It was also established from molecular orbital studies that the neighboring 5CB environment undergoes some sort of nonbonding interaction with the growing PEDOT chains and has resulted in the modification of solubility and few other properties of PEDOT. Therefore the PEDOT nanostructure obtained under the present synthesis condition is supposed to be a hybrid material having optical and electrical properties dominated by the PEDOT counterpart.

Optimal Power Flow Solution With an Embedded Center-Node Unified Power Flow Controller Using an Adaptive Grasshopper Optimization Algorithm

This paper proposes an adaptive grasshopper optimization algorithm (AGOA) for solving the optimal power flow (OPF) problem with the optimal incorporation of a center-node unified power flow controller (C-UPFC). The C-UPFC which is an advanced flexible AC transmission system (FACTS) device is inserted in series with a transmission line (TL) at its midpoint for providing the power flow control together with independent voltage control. The proposed AGOA is based on applying the Levy flight distribution and spiral path orientation of search agents to the traditional grasshopper optimization algorithm (GOA) to diminish the stagnation problem of the basic GOA at local optima and enhance its searching ability. Therefore, this AGOA technique is implemented for optimal sizing and siting of the C-UPFC on standard IEEE 30-bus and 57-bus systems as well as 26-bus system, and then compared with other well-known techniques to verify its effectiveness. To assess the installation of the C-UPFC in a power system, the optimal capacities and locations of the C-UPFC are determined for different objective functions, such as the fuel cost, fuel cost with a valve point loading effect (VPLE), piecewise cost and emission. Simulation results reveal that the proposed algorithm is more efficient and superior for OPF solution compared with the other algorithms reported in the literature. Furthermore, the optimal integration of the C-UPFC in the power system is considerably minimizing the power loss and improving the voltage profile.

High-performance and broadband chirality-dependent absorber based on planar spiral metasurface.

A perfect absorber is highly desired in many engineering applications, including cloaking devices and sensor detectors, but most types of absorbers with chirality-dependence have limited bandwidth. In this paper, we propose a novel broadband and chirality-dependent metasurface absorber that consists of an array of planar spiral elements. The spiral orientation can determine the absorption polarization, such as counterclockwise for right circular polarization (RCP) absorption and clockwise for left circular polarization (LCP) absorption. Three steps are adopted to enhance the absorption bandwidth: carefully optimizing the spiral turns, impedance of load resistor, and introducing a matching layer. To demonstrate our concept, we have designed and fabricated a realistic metasurface absorber. The numerical simulations are in good agreement with the experimental results. The simulation and measurement results demonstrate that this device can achieve a broadband (8.3-18 GHz) absorption for RCP incidence, while reflecting the LCP incident waves between 9 GHz to 17.8 GHz without changing its chirality. Our findings explore a novel way to realize broadband absorption and simultaneously provide a new strategy to design chirality-dependent multi-functional meta-devices.

Dependence of Thermodynamic Processes on Upstream Interplanetary Magnetic Field Conditions for Magnetosheath Ions

AbstractUsing Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations over a 10‐year period from 2008 to 2017, we statistically investigate the thermodynamic properties for magnetosheath ions and their dependence on upstream interplanetary magnetic field (IMF) conditions. The thermodynamic properties for magnetosheath ions are estimated by using the polytropic index averaged over the subinterval that belongs to the same streamline ( ). The THEMIS observations show that the probability distribution of for magnetosheath ions has a major peak at ~1 (quasi‐isothermal conditions) with a longer left tail down to ~0 (quasi‐isobaric conditions). The spatial distributions of for two different types according to IMF spiral angle (i.e., Parker spiral and ortho‐Parker spiral IMF orientations) reveal that the ions in the downstream of a quasi‐perpendicular shock (quasi‐perpendicular magnetosheath) exhibit quasi‐isothermal processes, while those in the downstream of a quasi‐parallel shock (quasi‐parallel magnetosheath) show lower than unity (down to ~0.8) implying the anticorrelation between the ion temperature and the ion number density variations. Moreover, in the quasi‐parallel magnetosheath tends to decrease with increasing magnetic local time distance from the magnetic local noon. These results indicate that the thermodynamic properties for magnetosheath ions depend on the bow shock geometry (quasi‐perpendicular bow shocks versus quasi‐parallel bow shocks) and are presumably controlled by a variety of instabilities, waves, and turbulence in the magnetosheath.

Recognition of Truncorotalia Crassaformis As a Modern Planktonic Foraminiferal Morphospecies in the Caribbean and Equatorial Atlantic Ocean and Proposal of a Neotype

AbstractTo clarify patterns of within-population variation in Truncorotalia crassaformis and their bearing on selection of a neotype, the shape of shells from two Caribbean sediment traps was analyzed statistically. These data were compared with those from a Holocene equatorial Atlantic core, from topotypes of Globigerina crassaformis Galloway and Wissler (Lomita Quarry, California), and from type specimens of Globorotalia oceanica. This approach was used because the holotype (now destroyed) was the only designated specimen. Morphometric analyses of shells in axial and spiral orientations use data from equally-spaced coordinates around their outlines recorded from SEM imagery. Special attention is given to the profile of the last-formed chamber and to development of a keel at its periphery. Comparison of data from 150 m and 700 m traps shows that the former population includes only small, possibly pre-adult specimens that are non-crusted. Shell shape, especially in axial orientation is much less variable than in the 700 m sample which includes many encrusted and kummerform specimens. Variation in the Holocene sample is closely similar to that in the 700 m trap. Between group comparisons show that the holotype and two paratypes of Globorotalia oceanica plot within the morphospaces of the trap and Holocene samples. All are referred to Truncorotalia crassaformis on the basis of their shape, calcification patterns, and notably the absence of a keel or carina on the final chamber. It is likely that its holotype had this attribute. The axial shape of the neotype is similar to the modelled mean shape of specimens from the sediment traps. Topotypes with a keel on all chambers of the outer whorl are identified as Truncorotalia aff. crassacarina.

Multisatellite observations of the magnetosphere response to changes in the solar wind and interplanetary magnetic field

Abstract. We employ multipoint observations of the Van Allen Probes, THEMIS, GOES and Cluster to present case and statistical studies of the electromagnetic field, plasma and particle response to interplanetary (IP) shocks observed by the Wind satellite. On 27 February 2014 the initial encounter of an IP shock with the magnetopause occurred on the postnoon magnetosphere, consistent with the observed alignment of the shock with the spiral IMF. The dayside equatorial magnetosphere exhibited a dusk–dawn oscillatory electrical field with a period of ∼330 s and peak-to-peak amplitudes of ∼15 mV m−1 for a period of 30 min. The intensity of electrons in the energy range from 31.5 to 342 KeV responded with periods corresponding to the shock-induced ULF (ultralow frequency) electric field waves. We then perform a statistical study of Ey variations of the electric field and associated plasma drift flow velocities for 60 magnetospheric events during the passage of interplanetary shocks. The Ey perturbations are negative (dusk-to-dawn) in the dayside magnetosphere (followed by positive or oscillatory perturbations) and dominantly positive (dawn-to-dusk direction) in the nightside magnetosphere, particularly near the Sun–Earth line within an L-shell range from 2.5 to 5. The typical observed amplitudes range from 0.2 to 6 mV m−1 but can reach 12 mV during strong magnetic storms. We show that electric field perturbations increase with solar wind pressure, and the changes are especially marked in the dayside magnetosphere. The direction of the Vx component of plasma flow is in agreement with the direction of the Ey component and is antisunward at all local times except the nightside magnetosphere, where it is sunward near the Sun–Earth line. The flow velocities Vx range from 0. 2 to 40 km s−1 and are a factor of 5 to 10 times stronger near noon as they correspond to greater variations of the electric field in this region. We demonstrate that the shock-induced electric field signatures can be classified into four different groups according to the initial Ey electric field response and these signatures are dependent on local time. Negative and bipolar pulses predominate on the dayside while positive pulses occur on the nightside. The ULF electric field pulsations of Pc and Pi types produced by IP shocks are observed at all local times and in the range of periods from several tens of seconds to several minutes. We believe that most electric field pulsations of the Pc5 type in the dayside magnetosphere at L&lt;6 are produced by field line resonances. We show that the direction of the shock normal determines the direction of the propagation of the shock-induced magnetic and plasma disturbances. The observed directions of velocity Vy predominately agree with those expected for the given spiral or orthospiral shock normal orientation.