Ultra-strong Magnetic Fields Research Articles

IXPE Observations of Magnetar Sources

Among the more than 60 sources observed in the first two years of operations, IXPE addressed four magnetars, neutron stars believed to host ultra-strong magnetic fields. We report here the main implication coming from IXPE measurements for the physics of magnetars. Polarimetric observations confirmed the expectations of high polarization degrees, up to ≈80%, values which have not been detected in any other source so far, providing further proof (independent from the P-P˙ estimate) that magnetars host indeed ultra-magnetized neutron stars. Polarization measurements also indicate that softer X-rays likely come from surface regions where the overlying atmosphere underwent magnetic condensation. The agreement of the phase-dependent polarization angle with a simple rotating vector model strongly supports the presence of vacuum birefringence around the star.

On the ultra-long spin period of 4U 1954+31

ABSTRACT 4U 1954$+$31 is a high-mass X-ray binary (HMXB) that contains a neutron star (NS) and an M supergiant companion. The NS has a spin period of $\sim 5.4$ h. The traditional wind-accreting model requires an ultra-strong magnetic field for the NS to explain its extremely long spin period, which seems problematic for the NS with age of a few $10^7$ yr. In this work, we take into account the unsteady feature of wind accretion, which results in alternation of the direction of the wind matter’s angular momentum. Accordingly, the torque exerted by the accreted wind matter varies between positive and negative from time to time, and largely cancels out over long time. In such a scenario, NSs can naturally attain long spin periods without the requirement of a very strong magnetic field. This may also provide a reasonable explanation for the spin period distribution of long-period NSs in HMXBs.

Новая модель эволюции Вселенной

Experiments and properties of low-energy nuclear reactions are presented.The existence of new ground states in the hydrogen atom, in the helium ion, and other hydrogen-like atoms located in a strong magnetic field at the appearance of third spatial oscillatory quantum number is shown. On the example of a transhelium atom, the possibility of pairing atomic electrons into an orthoboson is considered. The possibility of generating strong and ultra-strong magnetic fields in cosmic absolute plasma in the Photon era has been demonstrated, in which electrons recombine with protons and helium nuclei with the transition to transhydrogen and transhelium atoms. Transatoms combine into transmolecules and enter into multinuclear, radiation-free, low-energy reactions.The time of constant, natural nucleosynthesis has begun.The nucleosynthesis of carbon, nitrogen and oxygen atoms, when they were overwhelmingly surrounded by hydrogen atoms, led after the era of Recombination to intensive organic and bioorganic synthesis, which resulted in the origin of life and filling the entire Universe with that life. Low-energy nuclear reactions that occur in stars have been demonstrated.The possibility of natural nucleosynthesis occurring on Earth is shown.

В.И. Вернадский и новая парадигма

The main directions of V.I.Vernadsky's scientific activity during the period of the scientific revolution occurred at the end of the 19th and until the middle of the20th centuries are briefly listed. His decisive contribution to the initial research and practical application of the phenomenon of radioactivity and nuclear physics is shown. Based on the discovery of low-energy nuclear reactions more than 30 years ago, the development of Vernadsky's ideas about the role of radioactivity − the transformation of some chemical elements into other chemical elements − in geology, in the thermal balance of the Earth, in the prevalence of trace chemical elements is presented. Main provisions of the theory of low-energy nuclear reactions in condensed matter are listed: the threshold for excitation of the medium is indicated; shown is the possibility of generating a strong magnetic field in a unidirectional flow of electrons in a quasineutral plasma with the pairing of free electrons, and, subsequently, the pairing of atomic electrons into orthobosons with the latter forming a Bose-Einstein condensate, in which a new state of matter is formed − transatoms, which are combined, due to their ultra-strong magnetic fields, into nuclear transmolecule, in which multinuclear transmutation reactions occur with non-radioactive products; with the transformation of transmolecules into different sets of stable nuclei, subject to all conservation laws. In this case, the collective parameter that characterizes the quasi-equilibrium distribution of the mass numbers of isotopes – reaction products – is the “thermodynamic” coefficient of the energy content of the medium. Natural nucleosynthesis in the era of recombination of the Universe, which gave rise to the formation and development of organic chemical, and subsequently biochemical synthesis, is described. The development of Vernadsky's doctrine of the biosphere and noosphere of the Earth is supplemented by the concept of fractality of material, including biological structures with the further evolution of living matter, as well as by the concept of planetary nucleosynthesis. Starting from the idea of planetary nucleosynthesis, based on the mechanism of multinuclear quantum transitions of some atomic nuclei to others, a new doctrine of the geological development of the Earth and the foundations of quantum planetology were formulated, which explained the strict temporal cyclicity observed in the geological activity of the Earth associated with galactic jet energy flows. The issues discussed may become a basis for those directions in scientific research that will form a new paradigm, a new worldview.

Compact stars with ultrastrong magnetic fields in the approximation of exact spherical symmetry: Substantiation and application

Compact stars with ultrastrong magnetic fields in the approximation of exact spherical symmetry: Substantiation and application

Effects of ultra-strong static magnetic field on the gut microbiota of humans and mice.

To explore the effect of ultra-strong static magnetic field on gut microbiota, 16 T static magnetic field was used to study the changes in the structure and composition of human and mouse gut microbiota in this environment. In the mouse gut microbiota, at the genus level, the magnetic field significantly decreased the relative abundances of Escherichia-Shigella, Lactobacillus, Enterococcus, Burkholderia-Caballeronia-Paraburkholderia, Parasutterella, and Ralstonia and significantly increased those of Parabacteroides, Alloprevotella, Alistipes, Odoribacter, Bacteroides, Mucispirillum, Sutterella, and Prevotellaceae_UCG-001. Similarly, at the genus level, the relative abundances of Bacteroides, Parabacteroides, Romboutsia, and Streptococcus significantly decreased in the human gut microbiota. Contrary to the changing trend of the abundance in the mouse gut, the abundances of Bacteroides and Parabacteroides in the human gut were significantly reduced under magnetic field. The BugBase phenotypic prediction analysis showed that the relative abundances of five phenotypes, including anaerobism, mobile elements, potential pathogenicity, stress-tolerant, and biofilm formation, changed significantly in the mouse gut microbiota, while the relative abundances of two phenotypes, including Gram-positive and Gram-negative phenotypes, changed significantly in the human gut microbiota. The 16 T magnetic field could differently affect the composition, structure, and phenotypes of gut microbiota in human and mice, suggesting the importance of model selection in studying the biological effects of magnetic field.

Hydromagnetic Waves in Cold Nuclear Matter

I consider a proton–neutron fluid mixture placed in an ultra-strong external static magnetic field and derive the spin-independent, small-amplitude disturbances in infinitely extended systems. As a theoretical framework I adopt a hydrodynamical model for the proton and neutron fluids moving in a Skyrme mean-field derived from the time-dependent Hartree Fock formulation of the many-body nuclear problem. From the mass, momentum balance, and Maxwell equations, I set up a system of equations governing the electromagnetic field and the continuum-mechanical fields of the mixture. Next, the hydromagnetic equations are linearized, and the occurrence of small-amplitude distortions of the velocity field is analyzed for various orientations of the constant external magnetic induction with respect to the wave propagation vector. The derivation of the above equations is carried out for the inviscid case.

Time-dependent nuclear-electronic orbital Hartree-Fock theory in a strong uniform magnetic field.

In an ultrastrong magnetic field, with field strength B ≈ B0 = 2.35 × 105 T, molecular structure and dynamics differ strongly from that observed on the Earth. Within the Born-Oppenheimer (BO) approximation, for example, frequent (near) crossings of electronic energy surfaces are induced by the field, suggesting that nonadiabatic phenomena and processes may play a more important role in this mixed-field regime than in the weak-field regime on Earth. To understand the chemistry in the mixed regime, it therefore becomes important to explore non-BO methods. In this work, the nuclear-electronic orbital (NEO) method is employed to study protonic vibrational excitation energies in the presence of a strong magnetic field. The NEO generalized Hartree-Fock theory and time-dependent Hartree-Fock (TDHF) theory are derived and implemented, accounting for all terms that result as a consequence of the nonperturbative treatment of molecular systems in a magnetic field. The NEO results for HCN and FHF- with clamped heavy nuclei are compared against the quadratic eigenvalue problem. Each molecule has three semi-classical modes owing to the hydrogen-two precession modes that are degenerate in the absence of a field and one stretching mode. The NEO-TDHF model is found to perform well; in particular, it automatically captures the screening effects of the electrons on the nuclei, which are quantified through the difference in energy of the precession modes.

Ambipolar Heating of Magnetars

Magnetars, neutron stars thought to be with ultrastrong magnetic fields of 1014–15 G, are observed to be much hotter than ordinary pulsars with ∼1012 G, and additional heating sources are required. One possibility is heating by the ambipolar diffusion in the stellar core. This scenario is examined by calculating the models using the relativistic thermal evolutionary code without making the isothermal approximation. The results show that this scenario can be consistent with most of the observed magnetar temperature data.

Timing Noise Amplitudes of Magnetars During Outburst Episodes

Bu çalışmada magnetar kaynaklarının parlama süreçlerindeki gürültü genlikleri incelenmektedir. Gürültü genliği ölçümleri $\Delta_8$ ve $S_r$ olarak iki farklı teknik ile incelenmiştir. Gürültü genliklerinin bağımsız fiziksel parametreler ile olan ilişkileri incelenmiştir ve magnetarların parlama süresinde yaydıkları toplam enerji ile gürültü genlikleri arasında bağıntı olduğu ortaya koyulmaktadır. Bu bağıntıdan yola çıkarak magnetarların zamanlama gürültüsü oluşumunun radyo atarcalarla benzerlik gösterdiği ve bu süreçte asıl etkenin yüksek manyetik alan şiddeti olduğu tartışılmaktadır.

Естественный нуклеосинтез

The possibility of generating strong and ultrastrong magnetic fields in condensed ionized media in the presence of unidirectional motion of an ensemble of free electrons with a density > 1021 e/cm3 is demonstrated. It is shown that atomic and nuclear matter in strong and ultrastrong magnetic fields is transformed into a new state of matter - into transatom, in which atomic electrons and nuclear protons and neutrons are bound in pairs into orthobosons with a spin equal to unity S = 1ћ. Examples of radiationless, low-energy nuclear reactions of transatoms, including those without the Coulomb barrier between identical atomic nuclei, are presented. The mechanism of natural nucleosynthesis, based on the results of the low-energy nuclear reactions registered in various experiments in many laboratories of the world and on the creation of the theory of those reactions, at different stages of the development of the Universe, stars and planets is presented.

Effect of anomalous magnetic moment on the chiral transition at zero temperature in a strong magnetic field

The effect of the anomalous magnetic moment (AMM) on the chiral restoration is investigated at zero temperature in the strong magnetic fields with the vacuum magnetic regularization scheme. It is shown that the chiral restoration diagram sensitively depends on the AMM in the ultrastrong magnetic fields. In our work, the parameterization of AMM is employed as proportional to the square of the chiral condensate. The critical chemical potential is found to decrease linearly by the increasing coefficient in the AMM scale. At a smaller scale of the AMM, the critical chemical potential could go down and then grow up as the magnetic field increases. But at a larger scale, the magnetic catalysis on the critical chemical potential would not happen anymore.

A new scenario for magnetar formation: Tayler-Spruit dynamo in a proto-neutron star spun up by fallback

Magnetars are isolated young neutron stars characterised by the most intense magnetic fields known in the Universe, which power a wide variety of high-energy emissions from giant flares to fast radio bursts. The origin of their magnetic field is still a challenging question. In situ magnetic field amplification by dynamo action could potentially generate ultra-strong magnetic fields in fast-rotating progenitors. However, it is unclear whether the fraction of progenitors harbouring fast core rotation is sufficient to explain the entire magnetar population. To address this point, we propose a new scenario for magnetar formation involving a slowly rotating progenitor, in which a slow-rotating proto-neutron star is spun up by the supernova fallback. We argue that this can trigger the development of the Tayler-Spruit dynamo while other dynamo processes are disfavoured. Using the findings of previous studies of this dynamo and simulation results characterising the supernova fallback, we derive equations modelling the coupled evolution of the proto-neutron star rotation and magnetic field. Their time integration for different accreted masses is successfully compared with analytical estimates of the amplification timescales and saturation value of the magnetic field. We find that the magnetic field is amplified within 20 − 40 s after the core bounce, and that the radial magnetic field saturates at intensities between ∼1013 and 1015 G, therefore spanning the full range of a magnetar’s dipolar magnetic fields. The toroidal magnetic field is predicted to be a factor of 10–100 times stronger, lying between ∼1015 and 3 × 1016 G. We also compare the saturation mechanisms proposed respectively by H.C. Spruit and J. Fuller, showing that magnetar-like magnetic fields can be generated for a neutron star spun up to rotation periods of ≲8 ms and ≲28 ms, corresponding to accreted masses of ≳ 4 × 10−2 M⊙ and ≳ 1.1 × 10−2 M⊙, respectively. Therefore, our results suggest that magnetars can be formed from slow-rotating progenitors for accreted masses compatible with recent supernova simulations and leading to plausible initial rotation periods of the proto-neutron star.

Polarized x-rays from a magnetar.

Magnetars are neutron stars with ultrastrong magnetic fields, which can be observed in x-rays. Polarization measurements could provide information on their magnetic fields and surface properties. We observed polarized x-rays from the magnetar 4U 0142+61 using the Imaging X-ray Polarimetry Explorer and found a linear polarization degree of 13.5 ± 0.8% averaged over the 2- to 8-kilo-electron volt band. The polarization changes with energy: The degree is 15.0 ± 1.0% at 2 to 4 kilo-electron volts, drops below the instrumental sensitivity ~4 to 5 kilo-electron volts, and rises to 35.2 ± 7.1% at 5.5 to 8 kilo-electron volts. The polarization angle also changes by 90° at ~4 to 5 kilo-electron volts. These results are consistent with a model in which thermal radiation from the magnetar surface is reprocessed by scattering off charged particles in the magnetosphere.

Analytic approximations to photoabsorption cross sections of once-ionized helium in magnetar atmospheres

Magnetar atmospheres can contain a substantial fraction of once-ionized helium. At the magnetic fields about 1014 −1015 G, typical of magnetars, Landau quantization is important not only for the electrons, but also for the centre-of-mass (CM) motion of the He+ ion. The CM and internal motions are mutually dependent, which complicates theoretical studies of the He+ characteristics. We present asymptotic analytic expressions for the binding energies, oscillator strengths, and photoionization cross sections of the moving hydrogenlike ions in an ultra-strong magnetic field, which can be used to construct approximate models of magnetar atmospheres.

Axionlike Particles from Hypernovae.

It was recently pointed out that very energetic subclasses of supernovae (SNe), like hypernovae and superluminous SNe, might host ultrastrong magnetic fields in their core. Such fields may catalyze the production of feebly interacting particles, changing the predicted emission rates. Here we consider the case of axionlike particles (ALPs) and show that the predicted large scale magnetic fields in the core contribute significantly to the ALP production, via a coherent conversion of thermal photons. Using recent state-of-the-art supernova (SN) simulations, including magnetohydrodynamics, we find that, if ALPs have masses m_{a}∼O(10) MeV, their emissivity in such rare but exciting conditions via magnetic conversions would be over 2 orders of magnitude larger than previously estimated. Moreover, the radiative decay of these massive ALPs would lead to a peculiar delay in the arrival times of the daughter photons. Therefore, high-statistics gamma-ray satellites can potentially discover MeV ALPs in an unprobed region of the parameter space and shed light on the magnetohydrodynamical nature of the SN explosion.

Magnetoconduction in the Correlated Semiconductor FeSi in Ultrastrong Magnetic Fields up to a Semiconductor-to-Metal Transition.

Magnetoresistance of the correlated narrow-gap semiconductor FeSi was investigated by the radio frequency self-resonant spiral coil technique in magnetic fields up to 500T, which is supplied by an electromagnetic flux compression megagauss generator. Semiconductor-to-metal transition accomplishes around 270T observed as a sharp kink in the magnetoresistance, which implies the closing of the hybridization gap by the Zeeman shift of band edges. In the temperature-magnetic field phase diagram, the semiconductor-metal transition field is found to be almost independent of temperature, which is in contrast to a characteristic magnetic field associated with the hopping magnetoconduction in the in-gap localized states, exhibiting a notable temperature dependence.

On the Circular Polarization of Repeating Fast Radio Bursts

Abstract Fast spinning (e.g., sub-second) neutron star with ultra-strong magnetic fields (or so-called magnetar) is one of the promising origins of repeating fast radio bursts (FRBs). Here we discuss circularly polarized emissions produced by propagation effects in the magnetosphere of fast spinning magnetars. We argue that the polarization-limiting region is well beyond the light cylinder, suggesting that wave mode coupling effects are unlikely to produce strong circular polarization for fast spinning magnetars. Cyclotron absorption could be significant if the secondary plasma density is high. However, high degrees of circular polarization can only be produced with large asymmetries in electrons and positrons. We draw attention to the non-detection of circular polarization in current observations of known repeating FRBs. We suggest that the circular polarization of FRBs could provide key information on their origins and help distinguish different radiation mechanisms.

On the magnetic fields of ultraluminous X-ray pulsars

So far quite a few ultraluminous X-ray (ULX) pulsars have been discovered. In this work, we construct a super-Eddington, magnetic accretion disk model to estimate the dipole magnetic field of eight ULX pulsars based on their observed spin-up variations and luminosities. We obtain two branches of dipole magnetic field solutions. They are distributed in the range of B ∼ (0.156 – 64.5) × 1010 G and ∼ (0.275 – 79.0) × 1013 G corresponding to the low- and high-B solutions respectively. The low magnetic field solutions correspond to the state that the neutron stars are far away from the spin equilibrium, and the high magnetic field solutions are close to the spin equilibrium. The ultra-strong magnetic fields derived in Be-type ULX pulsars imply that the accretion mode in Be-type ULX pulsars could be more complicated than in the persistent ULX pulsars and may not be accounted for by the magnetized accretion disk model. We suggest that the transition between the accretor and the propeller regimes may be used to distinguish between the low- and high-B magnetic field solutions in addition to the detection of the cyclotron resonance scattering features.

GRAPHENE SENSORS IN FULL EFFECT

Graphene pioneer Paragraf continues to break new ground, with tests showing accurate operation can be sustained at mK temperature levels while simultaneously exposed to ultra-strong magnetic fields.