Lebedev Physical Institute Research Articles

Contents of the special issues of the journal "Physics-Uspekhi" dedicated to the 90th anniversary of the Lebedev Physical Institute (LPI)

Contents of the special issues of the journal "Physics-Uspekhi" dedicated to the 90th anniversary of the Lebedev Physical Institute (LPI)

Microwave radiation of space and prospects for its use in quantum propulsors

Using the original approach developed in recent years – supramolecular physics of the environment, the results of considering the contribution of physical optics processes to the formation of induced microwave radiation are presented.The two most powerful cosmic thermal sources: the background (relict) flux in the absolute millimeter maximum of the spectrum, and the mm-wave radio flux from Sun are considered. The postulate of A. Einstein about the emergence of an induced emission quantum in a medium with established thermal equilibrium is taken into account. This made it possible to quantitatively substantiate, based on the principles of the similarity theory of G.S. Golitsyn, a scheme for the use of microwave energy of the interstellar/interplanetary medium during space flights. Based on the physics of collisions, in the proton transfer reaction of the main simple hydrides in interstellar/interplanetary molecular clouds, it is proposed to take into account the possibility of the manifestation of an additional channel for the maser effect in such a medium (first considered by V.A. Ambartsumian in 1979) due to the close location of electronically excited Rydberg levels for molecules in these clouds. The pioneering work of N.S. Kardashev on the study of Rydberg transitions during the emission of recombination radio lines was taken into account. Due to the efforts of astronomers from the Lebedev Physical Institute and the State Astronomical Observatory of the Russian Academy of Sciences (at Pulkovo), this work led to the discovery of the microwave flux from deep space objects. Real energy and schemes for using a microwave quantum propulsor device with the ability to choose the direction of flights are discussed.

The Lebedev Physical Institute of the Russian Academy of Sciences (LPI) turned 90 years old

The Lebedev Physical Institute of the Russian Academy of Sciences (LPI) turned 90 years old

Analysis of the Causes of the Magnetic Storm on December 1–2, 2023 Based on Observations of Interplanetary Scintillations at the BSA Radio Telescope of the Lebedev Physical Institute

The results of the analysis of observational data of interplanetary scintillations obtained at the Big Synphasic Antenna radio telescope of the Lebedev Physical Institute (BSA LPI) before, during and after the magnetic storm that occurred on December 1–2, 2023. Observational data were compared with model calculations for corotating and propagating large-scale disturbances. The results of observations of scintillations of radio sources indicate that the magnetic storm that took place was caused by the superposition of two types of large-scale disturbances of the solar wind. On the day before the start of the magnetic storm, signs of interaction of the Earth’s magnetosphere with the corotating region of multi-velocity solar wind flows were observed, whereas later signs of disturbance of the magnetosphere by a coronal mass ejection propagating after the M9.8 flare on November 28, 2023 were observed.

Физическому институту им. П.Н. Лебедева Российской академии наук (ФИАН) — 90 лет

Физическому институту им. П.Н. Лебедева Российской академии наук (ФИАН) — 90 лет

ФОРМИРОВАНИЕ ЗАЩИТЫ ДЛЯ КОСМИЧЕСКИХ АППАРАТОВ ОТ НЕЙТРОНОВ

Together with the Lebedev Physical Institute, the research laboratory of JSC Avangard has developed a new shielding material against neutrons with different percentages of 10B called “wikineutron”. An experimental comparison of the new shielding material with synthesized ceramic materials based on boron carbide and tungsten boride was carried out. The “wikineutron” material has mass-dimensional characteristics that exceed existing analogues of shielding materials against neutrons, and can be recommended for the spacecraft shielding.

Fifty years of studying the GCR intensity during inversion of heliospheric magnetic fields I. Observations

The effects of the 22-year variation of solar magnetic fields in the galactic cosmic ray (GCR) intensity were first observed and interpreted as manifestations of inversion of the high-latitude solar magnetic field in properties of heliospheric magnetic fields by the Lebedev Physical Institute team in 1973. Since then, these effects have been studied already for 50 years.
 The situation with the heliospheric magnetic field is clear for periods of medium and low sunspot activity — the heliosphere consists of two unipolar “hemispheres” separated by a wavy global heliospheric current sheet and characterized by a general polarity A (unit quantity with the sign of the radial component of the heliospheric magnetic field in the northern hemisphere). Yet there is no consensus on what the inversion of the heliospheric magnetic field is and which effects in the GCR intensity are connected with this phenomenon.
 In this article, we briefly formulate general concepts of the 22-year variation in characteristics of the Sun, heliosphere, and GCR intensity and discuss the observed effects in the GCR intensity, which we attribute to the heliospheric magnetic field reversal. Models for this phenomenon and the results of GCR intensity calculations with these models will be discussed in the next article.

Пятьдесят лет исследования поведения интенсивности ГКЛ в периоды инверсии гелиосферного магнитного поля. I. Наблюдаемые эффекты

The effects of the 22-year variation of solar magnetic fields in the galactic cosmic ray (GCR) intensity were first observed and interpreted as manifestations of inversion of the high-latitude solar magnetic field in properties of heliospheric magnetic fields by the Lebedev Physical Institute team in 1973. Since then, these effects have been studied already for 50 years.
 The situation with the heliospheric magnetic field is clear for periods of medium and low sunspot activity — the heliosphere consists of two unipolar “hemispheres” separated by a wavy global heliospheric current sheet and characterized by a general polarity A (unit quantity with the sign of the radial component of the heliospheric magnetic field in the northern hemisphere). Yet there is no consensus on what the inversion of the heliospheric magnetic field is and which effects in the GCR intensity are connected with this phenomenon.
 In this article, we briefly formulate general concepts of the 22-year variation in characteristics of the Sun, heliosphere, and GCR intensity and discuss the observed effects in the GCR intensity, which we attribute to the heliospheric magnetic field reversal. Models for this phenomenon and the results of GCR intensity calculations with these models will be discussed in the next article.

Calibration Beam of Low-Energy Secondary Electrons at the Pakhra Accelerator of the Lebedev Physical Institute

Calibration Beam of Low-Energy Secondary Electrons at the Pakhra Accelerator of the Lebedev Physical Institute

Estimation of Energy Spectrum of Precipitating Magnetospheric Electrons Based on Bremsstrahlung X‐Ray Fluxes Recorded in the Atmosphere

AbstractNumerous energetic electron precipitation events were recorded since 1963 in the atmosphere at polar latitudes in the course of regular measurements of charged particle fluxes in the Earth's atmosphere being performed by the Lebedev Physical Institute. The experimental data obtained represent the only uniform database in the world on electron precipitation events recorded directly in the atmosphere well below satellite orbits. The precipitating electrons are absorbed in the upper atmosphere. However, they generate X‐rays that can penetrate deep into the atmosphere sometimes down to altitudes of 20–35 km accessible to balloon measurements. These experimental data allow studying energy, temporal and spatial characteristics of electron precipitation events. In particular, based on PLANETOCOSMICS/GEANT4 we developed a method for evaluating the energy spectra of the primary flux of precipitating electrons. This method was used for evaluation of primary spectra of precipitating electrons assuming exponential energy distribution of incident electrons. Now, for the development of the method, we present the possibility of determining the energy spectra of electrons in the power‐law form, using new software RUSCOSMICS code. This new method, based on the GEANT4 software, makes it possible to describe the transport of precipitating electrons in the atmosphere taking into account the evolution of the energy and pitch‐angle distributions of electrons and X‐ray photons.

Development of a Method for Recovery of the Energy Spectra of Precipitating Electrons from the Data of Measurements in the Atmosphere

Regular measurements of fluxes of charged particles in the Earth’s atmosphere conducted by theLebedev Physical Institute (LPI) made it possible to register since 1963 more than 500 cases of precipitationof energetic electrons in the northern polar latitudes. The obtained experimental data represent the world’sonly database on the precipitation of electrons registered directly in the Earth’s atmosphere. Primary precipitatingelectrons are absorbed in the upper layers of the atmosphere. However, the fluxes of secondary photonsgenerated by them can penetrate deep into the atmosphere, sometimes to heights of ~20 km, which areaccessible for balloon measurements by the Lebedev Physical Institute. This paper presents a new techniquefor reconstructing the energy spectrum of precipitating electrons developed on the basis of the Monte Carlosimulation of the processes of electron propagation in the atmosphere. The applicability of the technique tothe accumulated experimental data is shown, and new results are presented for individual events recorded inthe atmosphere.

The System of Anticoincidence Detectors of Space-Based Gamma-Ray Telescope GAMMA-400: The Characteristics Obtained Using Positron Beam of Synchrotron S-25R “PAKHRA” of the Lebedev Physical Institute, Russian Academy of Sciences

The System of Anticoincidence Detectors of Space-Based Gamma-Ray Telescope GAMMA-400: The Characteristics Obtained Using Positron Beam of Synchrotron S-25R “PAKHRA” of the Lebedev Physical Institute, Russian Academy of Sciences

R&D of carbon monoxide lasers at the Lebedev physical institute of the Russian academy of sciences (review)

R&D of carbon monoxide lasers at the Lebedev physical institute of the Russian academy of sciences (review)

Mathematical modeling of experiments on the interaction of a high-power ultraviolet laser pulse with condensed targets

Objectives. The paper aimed to review and analyze the results of works devoted to numerical modeling of experiments on the interaction of high-power ultraviolet (UV) laser pulses with condensed targets. The experiments were carried out at GARPUN, the powerful KrF-laser facility at the P.N. Lebedev Physical Institute of the Russian Academy of Sciences (Moscow). The relevance of the research is related to the use of excimer UV lasers as a driver for a thermonuclear reactor. Physical aspects of laser-plasma interaction, including those related to the possibility of using two-sided cone target in a fission-fusion reactor, are discussed.Methods. The research is based on physico-mathematical models, including Euler and Lagrange.Results. The mathematical modeling of three types of natural experiments is presented: (1) burning through different thicknesses of Al foils by high-power UV laser; (2) studying hydrodynamic instability development at the UV laser acceleration of thin polymer films and features of turbulent zone formation; (3) interaction of high-power UV laser pulses with two-layer targets (Al + Plexiglas) and study of fine structures. Numerical modeling showed that a hybrid reactor with UV laser driver can use targets in the form of two-sided counter cones.Conclusions. Physico-mathematical models are developed along with 2D codes in Lagrangian and Eulerian coordinates as confirmed in the results of natural experiments. The models can be used to describe the physics of high-power UV laser pulses interacting with various targets and forecast the results of reactor-scale experiments.

Творец и лидер. Николай Геннадиевич Басов 1922-2001

Like the titans of the Renaissance, N.G. Basov represented the heroic era of our science. He was both the leader and the scientist who coexisted in him in the closest possible way. You can say that he was an armchair scientist who defines, thinks over and solves scientific problems one on one. In 1952, thirty-year-old N.G. Basov was the first to point out the fundamental possibility of creating a molecular generator. In the next four years, he carried out work on its theoretical justification and experimental implementation working with the participation of a small group of young scientists, the eldest of whom was A.M. Prokhorov. Already in 1958, N.G. Basov started to organize work in the field of quantum electronics at the Lebedev Physical Institute under the auspices of the USSR Academy of Sciences, and in 1961 he delivered a concept paper on this subject at the All-Union Meeting of Scientists in the Kremlin. The article uses materials that appeared in the scientific literature and the media timed to the centenary of N.G. Basov, as well as impressions of joint work and meetings with him at the Lebedev Physical Institute and MEPhI.

Search for Pulsars in an Area with Coordinates 3h < α < 4h and +21° < δ < +42°

On the Large Phased Array (LPA) of Lebedev Physics Institute (LPI), a search for pulsars outside the Galaxy plane was carried out in a 300 sq. deg area. The search with a sensitivity 5-10 times better than that of previously conducted surveys was at a frequency of 111 MHz. The search was carried out in the summed power spectra. With an accumulation equivalent to 100 hours of continuous observations for each point of the area, 5 known pulsars were detected with a signal-to-noise ratio (S/N) from 20 to 1300 in the first harmonic of the spectrum. Average profiles were obtained for the detected pulsars. Estimates of the peak and integral flux densities of the found pulsars are given for individual sessions and for the power spectra summarized over 5.5 years, obtained using the developed method based on measurements of the height of harmonics in the power spectrum. No new pulsars have been detected in the area. Apparently, when searching for pulsars in the area, we have approached the lower limit of the luminosity of the second pulsars. The completeness of the survey is at the level of 0.5 mJy.

Pushchino multibeam pulsar search – I. Targeted search of weak pulsars

ABSTRACT The search for pulsars in a sample of pulsar candidates found based on a multi-year survey conducted with low (six channels; sampling 0.1s) time-frequency resolution on declinations −9° < δ < +42° was carried out with the Large Phased Array of the Lebedev Physical Institute (LPA LPI). LPA is a transit telescope operating at 111 MHz with a bandwidth of 2.5 MHz. Search, analysis and evidence of pulsar detection were carried out using a visualization programme of summed up power spectra obtained from the survey data with high (32 channels; sampling 12.5 ms) time-frequency resolution. 11 new pulsars with periods P0 = 0.41–3.75 s and dispersion measure DM = 15–154 pc cm−3 have been discovered. In total, in the survey with a low-time-frequency resolution for the period 2016–2021 in a blind search 203 pulsars were found, among them 42 new and 161 known pulsars. It is shown that in the search on the data with high-time-frequency resolution accumulated over a time interval of seven years, pulsars with a flux density of 0.1–0.2 mJy at the frequency of 111 MHz can be detected. When searching for pulsars with regular (periodic) emission at declinations +21° < δ < +42o, all pulsars located outside the galactic plane having P0 ≥ 0.5 s, DM ≤ 100 pc cm−3, and the flux density S ≥ 0.5 mJy can be detected.

Estimation of the FST-Layering Time for Shock Ignition ICF Targets

The challenge in the field of inertial confinement fusion (ICF) research is related to the study of alternative schemes for fuel ignition on laser systems of medium and megajoule scales. At the moment, it is considered promising to use the method of shock ignition of fuel in a pre-compressed cryogenic target using a focused shock wave (shock- or self-ignition (SI) mode). To confirm the applicability of this scheme to ICF, it is necessary to develop technologies for mass-fabrication of the corresponding targets with a spherically symmetric cryogenic layer (hereinafter referred to as SI-targets). These targets have a low initial aspect ratio Acl (Acl = 3 and Acl = 5) because they are expected to be more hydrodynamically stable during implosion. The paper discusses the preparation of SI-targets for laser experiments using the free-standing target (FST) layering method developed at the Lebedev Physical Institute (LPI). It is shown that, based on FST, it is possible to build a prototype layering module for in-line production of free-standing SI-targets, and the layering time, τform, does not exceed 30 s both for deuterium and deuterium-tritium fuel. Very short values of τform make it possible to obtain layers with a stable isotropic fuel structure to meet the requirements of implosion physics.

The Horizon-T cosmic ray experiment

Horizon-T experiment is deployed at the Tien Shan High-Altitude Scientific Station of the Lebedev Physical Institute of the Russian Academy of Sciences located at an altitude of 3340 m above sea level near the city of Almaty (Republic of Kazakhstan). The experiment is aimed at studying the temporal structure of Extensive Air Showers (EAS) from primary cosmic rays with energies above 1016eV, as well as studying delayed particles from the main shower front.Horizon-T consists of 10 detection points spaced up to 1400 m from each other and tied to a common center. The EAS-induced signals from all the detectors are transmitted via high-frequency cables to the central point and digitized with a resolution of 2 ns. This paper presents the physical justification, technical description, and calibration of the components of the experiment.

The specifics of pulsar radio emission

Abstract A characteristic property of pulsars is pulsed periodic radio emission, which has a high stability of periods. Despite the high stability of the emission periods of pulsars, monitoring the time of arrival of pulses (timing) shows the presence of different types of irregularities: variations of residual deviations, changes in the shape of the pulse, switching on and off of radio emission, and rotation discontinuities. Numerous observations of the radio emission of pulsars indicate that they are caused mainly by processes occurring in the pulsar’s magnetosphere. The special interest causes the observations of a pulsar in the Crab Nebula, performed, in particular, at Jodrell Bank and Pushchino Radio Astronomy Observatory of Lebedev Physical Institute. The connection between the scattering of radio pulses and the measure of the pulsar dispersion, which was established earlier in Pushchino together with Jodrell Bank, has been confirmed. The observed variations in the scattering of radio pulses and their partial correlation with the dispersion measure are explained by the eclipse of the pulsar by plasma clouds with electron density fluctuations significantly exceeding the corresponding fluctuations in the interstellar medium. The question of a possible connection between glitches, dispersion measure variations, radio pulses scattering, and gamma-ray flares is discussed.