Moiseev I.A., Sazhina O.S. «Constraints on Wormhole Formation from Phantom Dark Energy in DESI» Журнал экспериментальной и теоретической физики, 168, № 6, с. 833-842 (2025)

For dark energy (DE) being a dynamical field, an equation-of-state parameter w<–1 leads to the phantom DE state, allowing wormhole (WH) throats to be stabilized effectively. We investigated the possibility of the existence of traversable WHs, whose stability is fully ensured by phantom DE, the dominance of which was recently indicated by the DESI project. Within the framework of the simple Morris-Thorne model, we derived a phenomenological relation connecting the throat radius b with the energy density of the phantom dynamical field ρ_ph(z). This establishes a direct connection between cosmological parameters and the properties of traversable WHs, showing that phantom DE could, in principle, serve as the exotic matter required to sustain WHs with throat sizes spanning from the gravitational radii of stellar-mass BHs and SMBHs up to cosmological scales. We investigated possible WH formation channels and showed extreme suppression of two mechanisms (Euclidean instanton tunneling and thermal fluctuation nucleation). Using gravitational lensing SQLS constraints on Ellis-Bronnikov WHs, we quantified the fraction of phantom energy that can be trapped in such WHs, f≈10^–11, indicating that only a small fraction of the phantom DE can be trapped in WH throats. Overall, our results show both the theoretical consistency and the observational limitations of phantom-supported WHs.

Yu W., Starinova O.L. «Flight control in a halo orbit in vicinity of the L2 point in the Earth–Moon system using a solar sail» Вестник МГТУ им. Н.Э. Баумана. Серия: Машиностроение, № 2, с. 70-83 (2025)

In the context of the forthcoming Moon exploration and development initiatives, relay satellites for facilitating communication between the Earth and the Moon, particularly in regard to the far side and Polar Regions of the Moon, where permanent bases are planned, attract significant attention. This study focuses on the solar sails application in controlling motion of such relay satellites aimed at achieving efficient, precise, and long-term orbit keeping. A high-accuracy dynamic model of the spacecraft motion is created based on the ephemeris forecast of the celestial body motion, accompanied by the solar sail dynamic model with the controllable reflectivity. Using these models, the paper determines a reference halo orbit for the solar sail spacecraft in vicinity of the L2 point in the Earth–Moon system (EML2) through application of the multiple-shooting method. Subsequently, a solar sail control algorithm for tracking the reference orbit and applying the sliding mode method is developed, along with determination of the solar sail optimal parameters. A comparative analysis with the China's Queqiao relay satellite that utilizes chemical propulsion for the orbit keeping indicates that introduction of a solar sail could lead to the 66% reduction in the fuel mass for orbit keeping, and achieving the comparable orbit keeping capabilities Please cite this article as: Yu W., Starinova O.L. Flight control in a halo orbit in vicinity of the L2 point in the Earth–Moon system using a solar sail.

Moiseev A., Gololobov A., Ievenko I., Korsakov A., Petuhov I., Starodubtsev S. «Space weather research in Yakutia» Солнечно-земная физика, 11, № 3, с. 149-159 (2025)

The article reports on the studies of various manifestations of space weather (SW) on Earth, conducted by SHICRA SB RAS at the network of geophysical stations located in Yakutia. It is noted that the Institute researchers study various phenomena occurring in the solar wind and Earth's magnetosphere such as magnetic clouds, Forbush effects, magnetic storms, substorms and associated subauroral glow, as well as high-latitude impulses in the dayside magnetosphere and sudden phase anomalies in the lower ionosphere. In addition to the data from the network of stations in Yakutia, data from other domestic and foreign stations, as well as direct measurements of the parameters of the interplanetary medium and magnetosphere, carried out on various spacecraft, are used to study these phenomena. The paper also describes physical models of magnetic clouds in the solar wind, high-latitude disturbed ionosphere, and methods for short-term forecasting of SW based on cosmic ray (CR) measurements developed at SHICRA SB RAS.

Demidov M., Wang X.F., Sun Y.Z., Deng Y.Y. «Observations of solar large-scale magnetic fields with a new chinese telescope constructed for the International meridian circle program (IMCP)» Солнечно-земная физика, 11, № 3, с. 132-136 (2025)

One of the very important international events in space science that has happened recently is the launch of the International Meridian Circle Program (IMCP). A key element of IMCP is a quite new instrument – the Solar Full-disk Multi-layer Magnetograph (SFMM) installed at Gan Yu Solar Station (GYSS) of the Purple Mountain Observatory (Jiangsu Province). The main objective of this telescope is to provide data on distribution of magnetic fields across the solar surface, which is necessary for prediction of some space weather (SW) parameters since this information is actually the low boundary condition for corresponding numerical simulations. There are plans to construct a network of such telescopes (similar to GONG or to ngGONG), so it is very important to test how reliable the measurements of weak large-scale magnetic fields (LSMF) are with these instruments. It is just LSMF, not strong magnetic fields in active regions (which are relatively easy to measure), that determines the structure of the heliosphere. To do this, using first observations with SFMM at GYSS, is the main purpose of this study. After a brief description of the instrument and some methodical issues, we present the results of comparison of SFMM observations with the Wilcox Solar Observatory (WSO) data. WSO measurements of LSMF are the most reliable in the world, and the results of such comparison are extremely important. We have found out that the correlation coefficient is high enough (≈0.70) if we consider the whole range of measured strengths, but it is lower (≈0.57) if the consideration is rerstricted only to relatively weak (|B|≤10.0 G) fields. Note that there is a significant difference between regression coefficients (R) for these two cases: R≈5.1 in first case and only R≈1.8 in the second one. The reason of this is still unclear and will be the subject of future investigations.