Electromagnetic Dipoles Research Articles

Explaining the Bd,s→K∗K¯∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}_{d,s}\ o {K}^{\\left(\\ast \\right)}{\\overline{K}}^{\\left(\\ast \\right)} $$\\end{document} non-leptonic puzzle and charged-current B-anomalies via scalar leptoquarks

We present a model based on S1 scalar leptoquarks to solve the tension observed in the recently proposed non-leptonic optimized observables LK∗K¯∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {L}_{K^{\\ast }{\\overline{K}}^{\\ast }} $$\\end{document} and LKK¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {L}_{K\\overline{K}} $$\\end{document}. These observables are constructed as ratios of U-spin related decays based on Bd,s0→K∗0K¯∗0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}_{d,s}^0\ o {K}^{\\left(\\ast \\right)0}{\\overline{K}}^{\\left(\\ast \\right)0} $$\\end{document}. The model gives a one-loop contribution to the Wilson coefficient of the chromomagnetic dipole operator needed to explain the tension in both non-leptonic observables, while naturally avoiding large contributions to the corresponding electromagnetic dipoles. The necessary chiral enhancement comes from an O(1) Yukawa coupling with a TeV-scale right-handed neutrino running in the loop. We endow the model with a U(2) flavor symmetry, necessary to protect light-family flavor observables that otherwise would be in tension. Furthermore, we show that the same S1 scalar leptoquark is capable of simultaneously explaining the hints of lepton flavor universality violation observed in charged-current B-decays. The model therefore provides a potential link between two puzzles in B-physics and TeV-scale neutrino mass generation. Finally, the combined explanation of the B-physics puzzles unavoidably results in an enhancement of BB→Kνν¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{B}\\left(B\ o K\ u \\overline{\ u}\\right) $$\\end{document}, yielding a value close to present bounds.

An ultrathin triple‐band absorber for tuneable THz bio‐sensing

AbstractIn this paper, a multimode terahertz absorber is implemented using an ultrathin silicon ring with varying multimodal resonance. The rectangular silicon ring is providing three resonances with creating electromagnetic dipoles. The altering of these resonances is explicitly controlled with the help of a circular graphene ring. The graphene ring is used in the centre for tenability and to achieve perfect absorption. An equivalent circuit model is also presented and verified for the proposed structure. The design is intended to measure the glucose percentage in water. In addition, this can be used as a biosensor for the detection of malaria parasite percentage in water. A few important parameters like sensitivity and quality factors are considered to evaluate the performance of the said design. The sensitivity with analyte thickness is found to be 0.445 THz TU−1, 0.4255 THz TU−1, and 0.4305 THz TU−1. The corresponding quality factor is noted for the lower, middle, and upper bands as 235, 653, and 264 respectively. Further, the sensitivity and quality factors were measured just by changing the refractive index. The new estimated values are 0.480 THz RIU−1, 0.403 THz RIU−1, and 0.562 THz RIU−1 and corresponding quality factors are 203, 555, and 261 for lower, middle, and upper bands respectively. The design is also expected to flourish as a polarization‐insensitive absorber.

Chiral Mechanical Effect of the Tightly Focused Chiral Vector Vortex Fields Interacting with Particles.

The coupling of the spin-orbit angular momentum of photons in a focused spatial region can enhance the localized optical field's chirality. In this paper, a scheme for producing a superchiral optical field in a 4π microscopic system is presented by tightly focusing two counter-propagating spiral wavefronts. We calculate the optical forces and torques exerted on a chiral dipole by the chiral light field and reveal the chiral forces by combining the light field and dipoles. Results indicate that, in addition to the general optical force, particles' motion would be affected by a chiral force that is directly related to the particle chirality. This chiral mechanical effect experienced by the electromagnetic dipoles excited on a chiral particle could be characterized by the behaviors of chirality density and flux, which are, respectively, associated with the reactive and dissipative components of the chiral forces. This work facilitates the advancement of optical separation and manipulation techniques for chiral particles.

Incident angle dependent tunable multiband infrared absorption based sensor

The effect of electromagnetic (EM) resonance in the graphene resonator and multiple reflections taking place in the dielectric spacer can provide the multiband infrared absorption. The intensity of resonance spectrum occurring due to the formation of EM dipoles in resonator can be controlled by patterning it using desired perturbation. The absorber response can be set with the multiple narrow and broad absorption peaks together by modulating the electrical properties of graphene material. The proposed absorber provides the incident angle dependent behavior with linear variation in the resonant wavelengths by maintaining the high absorption. This can provide a new way of tuning the antenna response by angle of incidence. The implemented absorber can provide the triple narrow bands which can be utilized for performing the refractive index sensing. The proposed absorber provides a significant value of sensing performance parameters including sensitivity, full-width-half-maxima, and figure-of-merit with the high value of quality factor. Moreover, the proposed absorber offers the ability of generating an extra narrow absorption band in the case of presence of sensing analyte of specific thickness and refractive index range making it highly sensitive for the detection of specific surroundings including the bio-cells, chemicals and humidity in the air. The broadband characteristics of the proposer absorber can be utilized in implementing the infrared EM shields and thermal storage components.

Controlled-source electromagnetic modeling using a versatile secondary electric-field formulation and efficient multigrid-based preconditioner

Frequency-domain controlled-source electromagnetic (CSEM) surveying is a widely used geophysical electromagnetic exploration method. To avoid the singularity near the transmitting sources and improve the accuracy of three-dimensional (3D) CSEM forward modeling, we adopt the vector finite element method and secondary electric field formulation combined with hexahedral grids to solve the frequency-domain Maxwell equations. Primary field computation applies the fast Hankel transform using digital linear filters to quickly calculate the electromagnetic field generated by different electromagnetic dipoles or loops in the layered medium. Therefore, our forward modeling algorithm is highly versatile and compatible with various electromagnetic sources and scenarios of CSEM application (e.g., airborne, offshore, or marine). To improve the convergence rate, we use an algebraic multigrid solver based on the established Hiptmair–Xu decomposition. Using direct solvers requires a vast amount of memory, while conventional iterative solvers usually fail or converge only very slowly. Our new iterative scheme does not require the divergence corrections commonly applied in finite difference or finite volume electromagnetic modeling to accelerate the convergence. We implement complete parallelism in our finite element programming to efficiently solve the CSEM forward problems on massively parallel clusters. We use different numerical methods to obtain high-precision comparison results for one-dimensional and typical 3D models to demonstrate our algorithm's effectiveness and correctness. Finally, a public model of 3 million cells is used to simulate the responses of marine CSEM surveying. The proposed new solver shows robust scalability when using nearly 1000 cores on the cluster, demonstrating that our algorithm is particularly suitable for large-scale 3D forward modeling.

Development of a custom-made 2.8 T permanent-magnet dipole photon source for the ROCK beamline at SOLEIL.

In August 2021, the SOLEIL storage ring was restarted after the summer shutdown with a new bending magnet made entirely of permanent magnets. Producing a magnetic field of 2.8 T, it replaced one of the 32 electromagnetic dipoles (magnetic field of 1.7 T) of the ring to allow the ROCK beamline to exploit more intense photon fluxes in the hard X-ray range, thus improving the time resolution performances of the beamline for experiments carried out above 20 keV. The reduction of the new dipole magnetic gap required to produce the higher field has led to the construction and installation of a new vacuum vessel. The realization of the new dipole with permanent magnets was a technological feat due to the very strong magnetic forces. The permanent-magnet assembly required dedicated tools to be designed and constructed. Thanks to accurate magnetic measurements, a precise modelization of the new dipole was performed to identify its effects on the electron beam dynamics. The first measurements carried out on the ROCK beamline have highlighted the expected increase in photon flux, and the operation performances remain unchanged for the other beamlines. Here, the major developments and results of this innovative project are described in terms of technology, electron beam dynamics and photon beam performance on the ROCK beamline.

Measuring brain potentials of imagination linked to physiological needs and motivational states.

While EEG signals reflecting motor and perceptual imagery are effectively used in brain computer interface (BCI) contexts, little is known about possible indices of motivational states. In the present study, electrophysiological markers of imagined motivational states, such as craves and desires were investigated. Event-related potentials (ERPs) were recorded in 31 participants during perception and imagery elicited by the presentation of 360 pictograms. Twelve micro-categories of needs, subdivided into four macro-categories, were considered as most relevant for a possible BCI usage, namely: primary visceral needs (e.g., hunger, linked to desire of food); somatosensory thermal and pain sensations (e.g., cold, linked to desire of warm), affective states (e.g., fear: linked to desire of reassurance) and secondary needs (e.g., desire to exercise or listen to music). Anterior N400 and centroparietal late positive potential (LPP) were measured and statistically analyzed. N400 and LPP were differentially sensitive to the various volition stats, depending on their sensory, emotional and motivational poignancy. N400 was larger to imagined positive appetitive states (e.g., play, cheerfulness) than negative ones (sadness or fear). In addition, N400 was of greater amplitude during imagery of thermal and nociceptive sensations than other motivational or visceral states. Source reconstruction of electromagnetic dipoles showed the activation of sensorimotor areas and cerebellum for movement imagery, and of auditory and superior frontal areas for music imagery. Overall, ERPs were smaller and more anteriorly distributed during imagery than perception, but showed some similarity in terms of lateralization, distribution, and category response, thus indicating some overlap in neural processing, as also demonstrated by correlation analyses. In general, anterior frontal N400 provided clear markers of subjects' physiological needs and motivational states, especially cold, pain, and fear (but also sadness, the urgency to move, etc.), than can signal life-threatening conditions. It is concluded that ERP markers might potentially allow the reconstruction of mental representations related to various motivational states through BCI systems.

Broadband unidirectional transverse light scattering in a V-shaped silicon nanoantenna

The efficient manipulation of light-matter interactions in subwavelength all-dielectric nanostructures offers a unique opportunity for the design of novel low-loss visible- and telecom-range nanoantennas for light routing applications. Several studies have achieved longitudinal and transverse light scattering with a proper amplitude and phase balance among the multipole moments excited in dielectric nanoantennas. However, they only involve the interaction between electric dipole, magnetic dipole, and up to the electric quadrupole. Here, we extend and demonstrate a unidirectional transverse light scattering in a V-shaped silicon nanoantenna that involves the balance up to the magnetic quadrupole moment. Based on the long-wavelength approximation and exact multipole decomposition analysis, we find the interference conditions needed for near-unity unidirectional transverse light scattering along with near-zero scattering in the opposite direction. These interference conditions involve relative amplitude and phases of the electromagnetic dipoles and quadrupoles supported by the silicon nanoantenna. The conditions can be applied for the development of either polarization- or wavelength- dependent light routing on a V-shaped silicon and plasmonic nanoantennas.

Terahertz optical Hall effect in p-type monolayer hexagonal boron nitride on fused silica substrate.

We demonstrate for the first time, to the best of our knowledge, that the optical Hall effect (OHE) can be observed in p-type monolayer (ML) hexagonal boron nitride (hBN) on a fused silica substrate by applying linearly polarized terahertz (THz) irradiation. When ML hBN is placed on fused silica, in which the incident pulsed THz field can create local and transient electromagnetic dipoles, proximity-induced interactions can be presented. The Rashba spin-orbit coupling can be enhanced, and the in-plane spin component can be induced, along with the lifting of valley degeneracy. Thus, in the presence of linearly polarized THz radiation, the nonzero transverse optical conductivity (or Hall conductivity) can be observed. We measure the THz transmission through ML hBN/fused silica in the temperature range from 80 to 280 K by using THz time-domain spectroscopy in combination with an optical polarization examination. The Faraday ellipticity and rotation angle, together with the complex longitudinal and transverse conductivities, are obtained. The temperature dependence of these quantities is examined. The results obtained from this work indicate that ML hBN is a valleytronic material, and proximity-induced interactions can lead to the observation of OHE in the absence of an external magnetic field.

Multi-Bubble Universe Model: A Quantum-Relativistic Gravitational Theory of Space-Time

A multi-bubble model of universe is presented, in which gravity is the result of the aging of electromagnetic dipoles produced in quantum fluctuations of the action inside a condensate of a particular type of balancing gravitons. In the model, the exchange of gravitons among the dipoles and the potential of vacuum balances the energy of the fluctuation. The effect is to create bubbles of space-time that by growing they expand the local vacuum. The model suggests that the universe originates from overlapping of bubbles of space-time associated with dipoles. Matter is originated during gravitons decay. The use of the Bridge Theory demonstrates how the attractive force field that emerges in each bubble is in the first approximation in accordance with Newtonian gravity at small, medium and large distances in accordance with the theory of General Relativity by also introducing a variable cosmological term that justifies some observed cosmological anomalies. The model overcomes the current concepts of Dark Energy and Dark Mass in favor of a gravity produced by the curvature of space-time of the bubble. The existence of the balancing gravitons provides an estimate of the actual amounts of Dark Energy, Dark Matter and matter measured in the current universe. The estimated theoretical mass of the balancing gravitons is consistent with the Kaluza-Klein gravitons of 2.68 TeV observed in the ATLAS experiment during Run #1. Moreover, the use of the observational data of the rotation speeds of two samples of galaxies allows to verify the good agreement of the real universe with the model, providing a possible explanation of the variability in the measurement of the Hubble constant.

Behavior of Small Variable Mass Particle in Electromagnetic Copenhagen Problem

The paper presents the behavior of the motion properties of the variable mass test particle (third body), moving under the influence of the two equal primaries having electromagnetic dipoles. These primaries move on the same circular path around their common center of mass in the same plane. We have determined the equations of motion of the test particle whose mass varies according to Jean's law. Using the system of equations of motion we have evaluated the locations of equilibrium points, their movements and basins of the attracting domain. Finally, we examine the stability of these equilibrium points, all of which are unstable.

Strong Purcell effect for magnetic dipole emission with spoof plasmonic spiral structure

The ability to manipulate the interaction between light and optical emitters is essential for enhancing the capability of optical devices. Multifarious metallic and all-dielectric structures have been proposed frequently to enhance the emission of electromagnetic dipoles through the Purcell effect, in which its performances depend on two confinement mechanisms: temporal confinement (photon cavity period) and spatial confinement (localized light in an enclosed space), which can be described by the quality factor and mode volume, respectively. Here, we demonstrate that a hollow spoof plasmonic spiral structure in deep-subwavelength scale, which is constituted by periodically inserting spiral-shaped metallic arms into a hollow silicon cylinder, can drastically enhance emission of magnetic dipoles. Particularly, ultrahigh quality factor and ultrasmall mode volume of the magnetic resonance can be realized by further increasing the spiral degree of metallic arms. The results indicate that the quality factor of magnetic dipole mode in the structure can be enhanced to 2600 (silicon ∼ 5.5 for same scale) for spiral degree 4 π , and the Purcell factor can be enhanced to 5 × 10 6 (silicon ∼ 5.1 ) for a magnetic dipole emission. These results may provide a new avenue for designing optical cavities and enhancing magnetic dipole emission in low frequency.

Unified Physics and the Entanglement Nexus of Awareness

An analysis is made of the correlation between internal processes of the neurobiological system, which ostensibly generate the subjective qualia of experiential awareness, and the external environment which is comprised of objective phenomena. We describe a mechanism of vacuum-state correlation of quanta in the neurobiological system with spatially and/or temporally separated systems, resulting in a co-dependency of states. This is evaluated in the context of how strong correlation of the dipole moments (of charge and spin) of residues in biological polymers, such as deoxyribonucleic acid and microtubulin, are involved in the information processing of awareness, particularly memory, and are entangled across spatial and temporal domains (spacetime). Coherent electromagnetic emissions from both water nanostructures and associated biomolecules may modulate the electronic properties and thus behaviors of supramolecular systems, representing a significant signaling and regulatory mechanism functioning in tandem to the strong correlation of the spin and electromagnetic dipoles of polarizable structures in biological macromolecules. Strong coherence across macromolecular structures of the biological system and extension through spacetime via entanglement resolves the “binding problem” associated with the generation of conscious awareness by the brain, as it is not only the result of supposed computational activity of neuronal networks, but the integration of information from multiple reference frames across the entanglement network of spacetime. The entanglement nexus of spacetime, herein referred to as the unified spacememory network, emerges as a component of some of the recent elaborations of quantum spacetime architecture in the holographic mass solution to quantum gravity and unification. This is taken in consideration with the Susskind-Maldacena conformal field theory holographic equivalence conjecture that demonstrates the correspondence of micro-wormholes of Planck-scale dimension with quantum entanglement, resolving the information loss paradox and providing a physical and ontological explanation for nonlocality observed in quantum behavior. Together, these concepts describe an architecture of spacetime that is built from information and quantum entanglement through a micro-wormhole network. It is shown how the unified spacememory network is pivotal to engendering fundamental characteristics of awareness that are actively utilized in the macromolecular information systems of the biological organism.

Nuclear Physics with Magnetic Charges

The magnetic spinor particles (magnetic charges) are the real structural components all varieties of the Mass, for example, atoms, nucleons, positrons and neutrinos. Atomic-shaped device of Mass is the natural and the only possible organization of electric and magnetic charges which can create a gravitational field. At level of a popular language one can define nucleons as “small atoms”, and positron and neutrino as “very small atoms”. The electric and magnetic fundamental particles in neutron and proton shells which by tradition should be called quarks have charges of smaller magnitude than the charges of particles in atomic shells. Positron which participates in the gravitational interaction and, consequently, has an atomic-shaped device is the most likely candidate for the role of the proton nucleus. The most likely candidate particles on the participation in nuclei of proton and neutron as well as in nuclei of the positron and neutrino are presented in the article. So-called abnormal magnetic moment of neutron is formed by the quark magnetic dipoles which are like to unpaired electrons in the so-called magnetic atoms rotate on the outer orbitals of the neutron shell. The participation of the “magnetic electron” (magneton) in the neutrino core assumes the existence of the so-called anomalous magnetic moment and in the neutrino shell. The existence of real magnetic charges in the structures of the Mass draws our attention on such important problem as interaction between charges in the framework of electromagnetic dipoles such as and in which manifest the weak attraction. Weak interaction by its nature is electromagnetic. So-called electromagnetic interaction, manifested in pairs of homogeneous charges of opposite signs, is either electric or magnetic, but not electromagnetic. The explanation of the weak interaction in the marked pairs of charges is based on the author’s concept of the World Physical Triad and “Dark Energy”. Forces responsible for the interaction of the charges composing the electromagnetic dipoles correspond, conditionally of the weak charges of the particles which what assume mutual suppression of the influence of their fields on the Energo-medium and the formation of the weak “Dark energy”. Complex of magnetic particles, the quark magnetic dipoles and magneton by means of which the interconversion of a proton and a neutron is realized and maintained their constant number in the atomic nuclei can be called as magnetic meson. Namely, a processes of interconversion between a neutron and a proton which, as a rule, are not accompanied by secretions, created the illusion of neutron stability in atomic nuclei. The energy created by an exchange of magnetic mesons between neutron and proton can be a component of nuclear forces (strong interaction). Another effective and, most likely, the main component in the composition of the nuclear forces is the gravitational “Dark Energy”. Physics and structure of neutrinos presented in the paper suggest that the nature of these particles closer to the ideology of E. Majorana than P. Dirac’s.

Rotational and relative translational control for satellite electromagnetic formation flying in low earth orbit

PurposeThe purpose of this paper is to develop a theoretical design for the attitude control of electromagnetic formation flying (EMFF) satellites, present a nonlinear controller for the relative translational control of EMFF satellites and propose a novel method for the allocation of electromagnetic dipoles.Design/methodology/approachThe feedback attitude control law, magnetic unloading algorithm and large angle manoeuvre algorithm are presented. Then, a terminal sliding mode controller for the relative translation control is put forward and the convergence is proved. Finally, the control allocation problem of electromagnetic dipoles is formulated as an optimization issue, and a hybrid particle swarm optimization (PSO) – sequential quadratic programming (SQP) algorithm to optimize the free dipoles. Three numerical simulations are carried out and results are compared.FindingsThe proposed attitude controller is effective for the sun-tracking process of EMFF satellites, and the magnetic unloading algorithm is valid. The formation-keeping scenario simulation demonstrates the effectiveness of the terminal sliding model controller and electromagnetic dipole calculation method.Practical implicationsThe proposed method can be applied to solve the attitude and relative translation control problem of EMFF satellites in low earth orbits.Originality/valueThe paper analyses the attitude control problem of EMFF satellites systematically and proposes an innovative way for relative translational control and electromagnetic dipole allocation.

Design of a polarization-independent, wide-angle, broadband visible absorber

Many optical systems benefit from elements that can absorb a broad range of wavelengths over a wide range of angles, independent of polarization. In this paper, we present a polarization-independent, wide-angle, broadband absorber in the visible regime that exploits strong symmetric and asymmetric resonance modes of electromagnetic dipoles. It makes use of a bilayer cross-pattern structure which is simple, having five layers that include two stacks of metal ribbon in cross-patterns, two dielectric spacers and a metal reflecting layer. Simulations show that the design exhibits a significantly enhanced absorption property when compared to a device with a bilayer metal film structure or any other complex structure of cross-patterns that have no intersection angle. The maximum absorption efficiency of the device is 100% at resonances, and its absorption characteristics can be maintained over a wide range of angles of incidence – up to ± 60° – regardless of the incident polarization. This strategy can, in principle, be applied to other material systems and could be useful in diverse applications, including thermal emitters, photovoltaics and photodetectors.

Status of the ELIMED Beamline at the ELIMAIA facility

Laser-target acceleration represents a very promising alternative to conventional accelerators for several potential applications, from the nuclear physics to the medical ones. However, some extreme features, not suitable for multidisciplinary applications, as the wide energy and angular spreads, characterize optically accelerated ion beams. Therefore, beyond the improvements at the laser-target interaction level, a lot of efforts have been recently devoted to the development of specific beam-transport devices in order to obtain controlled and reproducible output beams. In this framework, a three years contract has been signed between the INFN-LNS (IT) and Eli-Beamlines-IoP (CZ) to provide the design and the realization of a complete transport beam-line, named ELIMED, dedicated to the transport, diagnostics and dosimetry of laser-driven ion beams. The transport devices will be composed by a set of super-strong permanent magnet quadrupoles able to collect and focus laser driven ions up to 70 MeV/u, and a magnetic chicane made of conventional electromagnetic dipoles to select particles within a narrow energy range. Here, the actual status of the design and development of these magnetic systems is described.

Design of a large acceptance, high efficiency energy selection system for the ELIMAIA beam-line

A magnetic chicane based on four electromagnetic dipoles is going to be realized by INFN-LNS to be used as an Energy Selection System (ESS) for laser driven proton beams up to 300 MeV and C6+ up to 70 MeV/u. The system will provide, as output, ion beams with a contrallable energy spread varying from 5% up to 20% according to the aperture slit size. Moreover, it has a very wide acceptance in order to ensure a very high transmission efficiency and, in principle, it has been designed to be used also as an active energy modulator. This system is the core element of the ELIMED (ELI-Beamlines MEDical and Multidisciplinary applications) beam transport, dosimetry and irradiation line that will be developed by INFN-LNS (It) and installed at the ELI-Beamlines facility in Prague (Cz). ELIMED will be the first user's open transport beam-line where a controlled laser-driven ion beam will be used for multidisciplinary research. The definition of well specified characteristics, both in terms of performance and field quality, of the magnetic chicane is crucial for the system realization, for the accurate study of the beam dynamics and for the proper matching with the Permanent Magnet Quadrupoles (PMQs) used as a collection system already designed. Here, the design of the magnetic chicane is described in details together with the adopted solutions in order to realize a robust system form the magnetic point of view. Moreover, the first preliminary transport simulations are also described showing the good performance of the whole beam line (PMQs+ESS).

Sliding mode control of electromagnetic tethered satellite formation

This paper investigates the control of tethered satellite formation actuated by electromagnetic dipoles and reaction wheels using the robust sliding mode control technique. Generating electromagnetic forces and moments by electric current coils provides an attractive control actuation alternative for tethered satellite system due to the advantages of no propellant consumption and no obligatory rotational motion. Based on a dumbbell model of tethered satellite in which the flexibility and mass of the tether is neglected, the equations of motion in Cartesian coordinate are derived. In this model, the J2 perturbation is taken into account. The far-field and mid-field models of electromagnetic forces and moments of two satellites on each other and the effect of the Earth’s magnetic field are presented. A robust sliding mode controller is designed for precise trajectory tracking purposes and to deal with the electromagnetic force and moment uncertainties and external disturbances due to the Earth’s gravitational and magnetic fields inaccuracy. Numerical simulation results are presented to validate the effectiveness of the developed controller and its superiority over the linear controller.

Equilibrium and station-keeping efficiency of cross-track multi-satellite arrays using a micro-electromagnetic formation flight

Electromagnetic formation flying is a novel concept of controlling the relative degrees of freedom of a satellite formation without the expenditure of fuel by using high-temperature superconducting wires to create magnetic dipoles. Micro-electromagnetic formation flying, which is an alternative to electromagnetic formation flying in terms of reduced complexity, uses conventional conductors to replace the high-temperature superconducting coils in electromagnetic formation flying, shortening the separation distances between the electromagnets. This paper investigates the use of micro-electromagnetic formation flying for providing relative position control for unperturbed station-keeping in a multi-satellite array along the cross-track direction that can be used in cross-track interferometric synthetic aperture radar applications. Considering that conventional conductors produce small separation distances between electromagnets, comparatively large baselines can be achieved by positioning multiple satellites consecutively in an array. The existence of equilibrium positions of the satellites is demonstrated. The station-keeping efficiency of the formation satellites is studied. It is found that the electromagnetic dipoles on neighboring satellites should be equal in magnitude and opposite in direction to obtain the maximum station-keeping efficiency of the formation; correspondingly, the equilibrium positions of the satellites along the cross-track direction are symmetrical about the center of mass of the formation. A method for maximizing the station-keeping efficiency of the formation using micro-electromagnetic formation flying is also presented, using feasible designs for small satellite formations as examples.