Enigmatic Gravity Effects Observed during Solar Eclipses. Their Analyse by Quantum Model of Inertia and Gravitation

Foucault long pendulums, with spherical suspended mass, show Earth rotation by the constant velocity drift of their oscillation plane. Maurice Allais used a short, 84 centimeters pendulum, with a suspended bronze disc mass. He recorded its oscillation plane drift velocity, during solar eclipses, in 1954 and 1959. Both times, he noticed an anomalous drift of the oscillation plane. Several authors confirmed the effect, during next solar eclipses, with other types of pendulums. Then a group of Geophysicists, from the Science Academy of China, used an accurate digital gravimeter to measure Earth Gravity acceleration during March 09, 1997 solar eclipse. Their gravimeter recorded two drops of Earth Gravity acceleration (respectively 5.02 and 7.7 µ Gals) before and during first and last contacts of the Moon disc. However there was no acceleration drop during eclipse totality. Same phenomena were confirmed later, during next solar eclipses, with the same gravimeter. No classical causes for these facts were found, since modern gravimeters take care of temperature and atmospheric pressure variations. We analyse the effect of Moon rotation, and of solar Corona mass, in the frame of our Quantum model of Inertia and of Gravitation. The model predicts that Moon / Earth Gravity acceleration changes, when the Moon direction is close to the Sun one, as observed from the gravimeter place. That phenomenon should be tied to Quantum fluctuations dispersion by matter. Recorded measurements confirm that interpretation.

Ebysus, a Multi-Fluid Multi-Species (MFMS) code: Application to magnetic reconnection in the solar atmosphere

<p>The solar atmosphere is composed of many species with a large number of ionization levels. Depending on the region considered, the plasma can be partially or fully ionized, weakly or strongly magnetized, weakly or strongly collisional, allowing for thermal non-equilibrium processes and chemical reactions. Recent observations of the IRIS mission (De Pontieu et al. 2014) have confirmed that the solar atmosphere is a complex environment involving a wide range of unsteady processes occurring at different temporal and spatial scales.</p><p>In this context, we have developed a new code Ebysus (see Martinez-Sykora et al., 2019), by expanding the state-of-the-art single-fluid radiative MHD code Bifrost (Gudiksen et al. 2011). Ebysus solves a full MultiFluid MultiSpecies (MFMS)  system of equation for any species and/or ionized/excited level as desired separately. Following Wargnier et al. 2020, an accurate description of the collisions for multicomponent plasmas in solar atmosphere conditions, consistent with the kinetic theory, has also been developed and implemented in the code. The code includes non-equilibrium (NEQ) ionization, recombination, excitation and de-excitation for any species, momentum exchange, electric forces due to velocity drift between different ionized species, thermal conduction and radiative losses. The whole numerical strategy has been tested and the modules needed for this proposal are fully implemented.</p><p>First, we will present the model and its numerical strategy. We will then focus on realistic magnetic reconnection (MR) events and perform numerical simulations in several conditions representative of different layers of the solar atmosphere. In particular, we will demonstrate the role of the drift velocities between different species on the reconnection rate and the formation of plasmoid instabilities, which leads to a high energy release. These instabilities play a significant role in the dynamics of chromospheric jets, as observed by IRIS (Rouppe et al. 2017). This strategy will be a crucial point in understanding MR events that occur during UV bursts or flares.</p>

Collisional polarization of molecular ions: a signpost of ambipolar diffusion

Magnetic fields play a role in the dynamics of many astrophysical processes, but they are hard to detect. In a partially ionized plasma, a magnetic field works directly on the ionized medium but not on the neutral medium, which gives rise to a velocity drift between them: ambipolar diffusion. This process is suggested to be important in the process of star formation, but has never been directly observed. We introduce a method that could be used to detect ambipolar diffusion and the magnetic field that gives rise to it, where we exploit the velocity drift between the charged and neutral medium. By using a representative classical model of the collision dynamics, we show that molecular ions partially align themselves when a velocity drift is present between the molecular ion and its main collision partner H2. We demonstrate that ambipolar diffusion potently aligns molecular ions in regions denser than their critical density. We include a model for HCO+ and show that collisional polarization could be detectable for the ambipolar drifts predicted by numerical simulations of the inner protostellar disk regions. The polarization vectors are aligned perpendicular to the magnetic field direction projected on the plane of the sky.

Mode conversion of two-fluid shocks in a partially-ionised, isothermal, stratified atmosphere

Context. The plasma of the lower solar atmosphere consists of mostly neutral particles, whereas the upper solar atmosphere is mostly made up of ionised particles and electrons. A shock that propagates upwards in the solar atmosphere therefore undergoes a transition where the dominant fluid is either neutral or ionised. An upwards propagating shock also passes a point where the sound and Alfvén speed are equal. At this point the energy of the acoustic shock can separated into fast and slow components. The way the energy is distributed between the two modes depends on the angle of magnetic field. Aims. We aim to investigate the separation of neutral and ionised species in a gravitationally stratified atmosphere. The role of two-fluid effects on the structure of the shocks post-mode-conversion and the frictional heating is quantified for different levels of collisional coupling. Methods. Two-fluid numerical simulations were performed using the (PIP) code of a wave steepening into a shock in an isothermal, partially-ionised atmosphere. The collisional coefficient was varied to investigate the regimes where the plasma and neutral species are weakly, strongly, and finitely coupled. Results. The propagation speeds of the compressional waves hosted by neutral and ionised species vary and, therefore, velocity drift between the two species is produced as the plasma attempts to propagate faster than the neutrals. This is most extreme for a fast-mode shock. We find that the collisional coefficient drastically impacts the features present in the system, specifically the mode conversion height, type of shocks present, and the finite shock widths created by the two-fluid effects. In the finitely-coupled regime, fast-mode shock widths can exceed the pressure scale height, which may lead to a new potential observable of two-fluid effects in the lower solar atmosphere.

The Transit and Light Curve Modeller

ABSTRACT Transit and Light Curve Modeller (TLCM), a computer code with the purpose of analysing photometric time series of transits simultaneously with the out-of-transit light variations and radial velocity curves of transiting/eclipsing binary systems, is presented here. Joint light-curve and radial velocity fits are possible with it. The code is based on the combination of a genetic algorithm and simulated annealing. Binning, beaming, reflection, and ellipsoidal effects are included. Both objects may have their own luminosities and therefore one can use TLCM to analyse the eclipses of both exoplanet and well-detached binary systems. A simplified Rossiter–McLaughlin effect is included in the radial velocity fit, and drifts and offsets of different instruments can also be fitted. The impact of poorly known limb darkening on the Rossiter–McLaughlin effect is shortly studied. TLCM is able to manage red-noise effects via wavelet analysis. It is also possible to add parabolic or user-defined baselines and features to the code. I also predict that light variations due to beaming in some systems exhibiting radial velocity drift should be observed by, e.g. PLATO. The fit of the beaming effect is improved by invoking a physical description of the ellipsoidal effects, which has an impact on the modelling of the relativistic beaming; I also point out the difficulties that are stemming from the fact that beaming and first-order reflection effects have the same form of time dependence. Recipe is given, which describes how to analyse grazing transit events. The code is freely available.

Kinematics of neutral and ionzied gas in the candidate protostar with efficient magnetic braking B335

Ambipolar diffusion can cause a velocity drift between ions and neutrals. This is one of the non-ideal MHD effects proposed to enable the formation of large Keplerian disks with sizes of tens of au (Zhao et al. 2018). To observationally study ambipolar diffusion in collapsing protostellar envelopes, we analyzed the ALMA H13CO+ (3–2) and C18O (2–1) data of the protostar B335, which is a candidate source with efficient magnetic braking (Yen et al. 2015). We constructed kinematical models to fit the velocity structures observed in H13CO+ and C18O. With our kinematical models, the infalling velocities in H13CO+ and C18O are both measured to be 0.85 ± 0.2 km s−1 at a radius of 100 au, suggesting that the velocity drift between the ionized and neutral gas is at most 0.3 km s−1 at a radius of 100 au in B335. The Hall parameter for H13CO+ is estimated to be ≫1 on a 100 au scale in B335, so that H13CO+ is expected to be attached to the magnetic field. Our non-detection or upper limit of the velocity drift between the ionized and neutral gas could suggest that the magnetic field remains rather well coupled to the bulk neutral material on a 100 au scale in B335, and that any significant field-matter decoupling, if present, likely occurs only on a smaller scale, leading to an accumulation of magnetic flux and thus efficient magnetic braking in the inner envelope in B335.

Constraint on ion–neutral drift velocity in the Class 0 protostar B335 from ALMA observations

Aims. Ambipolar diffusion can cause a velocity drift between ions and neutrals. This is one of the non-ideal magnetohydrodynamics (MHD) effects proposed to enable the formation of large-scale Keplerian disks with sizes of tens of au. To observationally study ambipolar diffusion in collapsing protostellar envelopes, we compare here gas kinematics traced by ionized and neutral molecular lines and discuss the implication on ambipolar diffusion. Methods. We analyzed the data of the H13CO+ (3–2) and C18O (2–1) emission in the Class 0 protostar B335 obtained with our ALMA observations. We constructed kinematical models to fit the velocity structures observed in the H13CO+ and C18O emission and to measure the infalling velocities of the ionized and neutral gas on a 100 au scale in B335. Results. A central compact (~1′′–2′′) component that is elongated perpendicular to the outflow direction and exhibits a clear velocity gradient along the outflow direction is observed in both lines and most likely traces the infalling flattened envelope. With our kinematical models, the infalling velocities in the H13CO+ and C18O emission are both measured to be 0.85 ± 0.2 km s−1 at a radius of 100 au, suggesting that the velocity drift between the ionized and neutral gas is at most 0.3 km s−1 at a radius of 100 au in B335. Conclusions. The Hall parameter for H13CO+ is estimated to be ≫1 on a 100 au scale in B335, so that H13CO+ is expected to be attached to the magnetic field. Our non-detection or upper limit of the velocity drift between the ionized and neutral gas could suggest that the magnetic field remains rather well coupled to the bulk neutral material on a 100 au scale in this source, and that any significant field-matter decoupling, if present, likely occurs only on a smaller scale, leading to an accumulation of magnetic flux and thus efficient magnetic braking in the inner envelope. This result is consistent with the expectation from the MHD simulations with a typical ambipolar diffusivity and those without ambipolar diffusion. On the other hand, the high ambipolar drift velocity of 0.5–1.0 km s−1 on a 100 au scale predicted in the MHD simulations with an enhanced ambipolar diffusivity by removing small dust grains, where the minimum grain size is 0.1 μm, is not detected in our observations. However, because of our limited angular resolution, we cannot rule out a significant ambipolar drift only in the midplane of the infalling envelope. Future observations with higher angular resolutions (~0. ′′1) are needed to examine this possibility and ambipolar diffusion on a smaller scale.

Global outburst of methanol maser in G24.33+0.14

A strong outburst of 6.7 GHz methanol maser occurred in the high-mass young stellar object (HMYSO) G24.33+0.14 between November 2010 and January 2013. The target was observed with the Torun 32 m radio telescope as a part of a long-term monitoring programme. Almost all twelve spectral features from 108 to 120 km s−1 varied synchronously with time delays between the flux minima of about two weeks. This may indicate that the variability is driven by global changes in the pump rate. The flare peaks of the two features with the highest relative amplitude of 40-60 are delayed by about 2.5 months while their profiles undergo essential transformation with a velocity drift of 0.23 km s−1yr−1. This may suggest that the variability is caused by a rapid increase of the pump rate and excitation of a large portion of the HMYSO environment by an accretion event.

Random walk on spheres method for solving drift-diffusion problems

The well-known random walk on spheres method (RWS) for the Laplace equation is here extended to drift-diffusion problems. First we derive a generalized spherical mean value relation which is an extension of the classical integral mean value relation for the Laplace equation. Next we give a probabilistic interpretation of the kernel. The distribution on the sphere generated by this kernel is then related to the von Mises–Fisher distribution on the sphere which can be efficiently simulated. The rigorous expressions are given for the case of constant velocity drift, but the algorithm is then extended to solve drift-diffusion problems with arbitrary varying drift velocity vector. Applications to cathodoluminescence and EBIC imaging of defects and dislocations in semiconductors are discussed.