High-frequency Magnetic Fluctuations in Space Plasmas and the Role of Electron Landau Damping

While low-frequency plasma fluctuations in the interplanetary space have been successfully described in the framework of classical turbulence, high-frequency fluctuations still represent a challenge for theoretical models. At these scales, kinetic plasma processes are at work, but although some of them have been identified in spacecraft measurements, their global effects on observable quantities are sometimes not fully understood. In this paper we present a new framework to the aim of describing the observed magnetic energy spectrum and directly identify in the data the presence of Landau damping as the main collisionless dissipative process in the solar wind.

MOSCOW INTERNATIONAL SYMPOSIA ON SOLAR SYSTEM RESEARCH (10M-S3 AND 11M-S3) REPORTS REVIEW. Part 1. Mars exploration

A review of the reports of the last two Moscow International Symposia on Solar System Research has been completed. In the first part of the review, 43 reports of the main session of the "Mars" section are considered. The works of leading experts in the field of planetary science cover a wide range of scientific and applied problems - from the study of the geological history and climate of Mars, the search for traces of life and subsurface water reserves, to new technologies in planetary research, mission planning, as well as monitoring solar activity and radiation conditions in the interplanetary space, orbit and the surface of Mars. The data obtained in the last two decades has made it possible to significantly advance in understanding the nature of Mars, but many unresolved questions remain regarding the climate in the early era, the existence of the Martian oceans in the past, biological and geological activity. The scientific results obtained by unmanned spacecraft should be fully taken into account in the development of manned deep space exploration programs. Key words: Solar system, planetology, international symposium, deep space, automatic interplanetary stations, Mars, Moon, reports review

ПАЛОЧНИКИ КАК ФАКТОР ПОЧВООБРАЗОВАНИЯ

Изучение существ – создателей важнейшего компонента жизни на планете – почвы, скорее всего, важная часть подготовки межпланетных космических команд. Работа представляет собой многоплановое исследование, где главным объектом выступает насекомое – Палочник аннамский. Автором проведены наблюдения за пищевой активностью и получены данные о количестве помета, то есть скорости формирования будущего гумуса. Проведено выращивание комнатного растения хлорофитум и оценено влияние смеси песка и гуано палочника на рост листьев и корней. Автору удалось провести серию химических анализов на количество нитратов в полученной «почве». Оценка концентрации нитратов в грунте проводилась как с помощью реагентов, так и с использованием прибора «Соэкс Эковизор F4». С их помощью получены данные о разных по времени формирования «почвах». The study of the creatures - creators of the most important component of life on the planet - the soil, first of all, is an important part of the preparation of interplanetary space teams. The work is a multifaceted study, where the main object is the insect – the Annam stick insect. The author carried out observations of food activity and obtained data on the amount of litter, that is, the rate of formation of future humus. A chlorophytum houseplant was grown and the effect of a mixture of sand and stick insect guano on the growth of leaves and roots was evaluated. The author managed to conduct a series of chemical analyses for the amount of nitrates in the resulting "soil". The assessment of the nitrate concentration in the soil was carried out both with the help of reagents and with the use of the device "Soex Ecovisor F4". With their help, data on "soils" of different formation times were obtained.

Observational results of MUSER during 2014–2019

The solar radio signal that can be received by the ground-based telescopes covers a wide frequency range, allowing us to monitor the complex physical processes occurred from the solar surface to the vast interplanetary space. MingantU SpEctral Radioheliograph (MUSER), as the latest generation of solar dedicated radio spectral-imaging instrument in the centimeter-decimeter wavelengths, has accumulated a large number of observational data since its commissioning observation in 2014. This paper presents the main observational results identified by MUSER from 2014 to 2019, including the quiet Sun and 94 solar radio burst events. We find that there are 81 events accompanied with Geostationary Operational Environmental Satellites (GOES) soft X-ray (SXR) flares, among which the smallest flare class is B1.0. There are 13 events without accompanying any recorded flares, among which the smallest SXR intensity during the radio burst period is equivalent to level-A. The main characteristics of all radio burst events are presented, which shows the powerful ability of MUSER to capture the valuable information of the solar non-thermal processes and the importance for space weather. This work also provides a database for further in-depth research.

Three-Dimensional Simulation Study of the Interactions of Three Successive CMEs during 4–5 November 1998

In this paper, using a 3D magnetohydrodynamics (MHD) numerical simulation, we investigate the propagation and interaction of the three halo CMEs originating from the same active region during 4–5 November 1998 from the Sun to Earth. Firstly, we try to reproduce the observed basic features near Earth by a simple spherical plasmoid model. We find that the first component of the compound stream at 1 AU is associated to the first CME of the three halo CMEs. During the propagation in the interplanetary space, the third CME overtakes the second one. The two CMEs merge to a new, larger entity with complex internal structure. The magnetic field of the first CME in the three successive CMEs event is compressed by the following complex ejecta. The interaction between the second and third CME results in the deceleration of the third CME and the enhancement of the density, total magnetic field and south component of the magnetic field. In addition we study the contribution of a single CME to the final simulation results, as well as the effect of the CME–CME interactions on the propagation of an isolated CME and multiple CMEs. This is achieved by analysing a single CME with or without the presence of the preceding CMEs. Our results show that the CME moves faster in a less dense, faster medium generated by the interaction of the preceding CME with the ambient medium. In addition, we show that the CME–CME interactions can greatly alter the kinematics and magnetic structures of the individual events.

Statistical Study of Small-Scale Interplanetary Magnetic Flux Ropes in the Vicinity of the Heliospheric Current Sheet

The small-scale interplanetary magnetic flux ropes (SIMFRs) are common magnetic structures in the interplanetary space, yet their origination is still an open question. In this article, we surveyed 63 SIMFRs found within 6-day window around the heliospheric current sheet (HCS) and investigated their axial direction, as well as the local normal direction of the HCS. Results showed that the majority (48/63) of the SIMFRs were quasi-parallel to the associated HCS (i.e., the axial direction of SIMFRs was quasi-perpendicular to the normal direction of the associated HCS). They also showed that the SIMFRs quasi-parallel to the associated HCS statistically had shorter duration than the cases quasi-perpendicular. The results indicate that most of these SIMFRs may be generated in the nearby HCSs.

On the Origin of ULF Magnetic Waves Before the Taiwan Chi-Chi 1999 Earthquake

The ultra low frequency (ULF) electromagnetic (EM) wave activity usually recorded on Earth’s ground has been found to depend on various types of space weather. In addition ULF waves observed before an earthquake have been hypothesized to be a result of geotectonic processes. In this study we elaborate for the first time the origin of sub-ULF (<1 msec) magnetic field waves before an earthquake (Chi-Chi/Taiwan, 20.9.1999) by comparing simultaneously obtained measurements in the interplanetary space (ACE satellite) and on the Earth’s ground (Taiwan). The most striking result of our data analysis, during a period of 7 weeks, is that the detection of four groups of sub-ULF waves in Taiwan coincide in time with the quasi-periodic detection of two solar wind streams by the satellite ACE with approximately the solar rotation period (∼28 days). The high speed solar wind streams (HSSs) in the interplanetary space were accompanied by sub-ULF Alfvén wave activity, quasi-periodic southward IMF and solar wind density perturbations, which are known as triggering agents of magnetic storm activity. The four HSSs were followed by long lasting decreases in the magnetic field in Taiwan. The whole data set examined in this study strongly suggest that the subULF magnetic field waves observed in Taiwan before the Chi-Chi 1999 earthquake is a normal consequence of the incident of HSSs to the magnetosphere. We provide some observational evidence that the sub-ULF electromagnetic radiation on the Earth was most probably a partner to (not a result of) geotectonic processes preparing the Taiwan 1999 earthquake.

Influence of the temperature of the photosphere and deeper layers of the Sun on the spectra of gamma quanta with energies above 511 keV during solar flares

Gamma-ray quanta, which occur during solar flares due to the interaction of accelerated protons with the photosphere and deeper layers of the sun, enter interplanetary space from a thickness of several tens of g/cm2. In the presented work, gamma quanta with energies of more than 511 keV are considered. This makes it possible to exclude from consideration the dependence of the probability of ortho- and parapositronium formation on the temperature and density of the solar matter. And also do not consider the probability of annihilation by two or 3 gamma quanta. Thus, the reactions of thermal neutrons remain dependent on the temperature. As the ambient temperature increases, the average number of elastic neutron scattering before capture increases. This leads to a more likely penetration of neutrons to a greater depth or their departure into the interplanetary space. The high temperature of the Sun below the photosphere may be one of the reasons for the absence of the 2.223 MeV line in solar flares with registered protons in the PAMELA and AMS2 experiments. Using the GEANT4 package, the spectra of gamma-quanta arising in nuclear interactions are calculated. The temperature-dependent features of the gamma-ray spectra are discussed.

Rutherford’s extended formula and optimization of the gravity assists beam modelling in the Solar system

Rutherford’s formula for the scattering of charged α-particles in the Coulomb field can be easily generalized to the case of gravitational scattering. The extended Rutherford formula for the gravitational scattering is presented. One of the types of the gravitational scattering in the Solar system is the gravity assist maneuvers. In this paper, an effective gravitational scattering cross-section is introduced by analogy for them and the generalized Rutherford formula for gravitational scattering is presented out when performing gravity assists. Modern methods of the ballistic design of the interplanetary space flights using gravity assist maneuvers around planets [1-3] are associated with the need to calculate a lot of trajectories (i.e. of the phase beams). For their effective use it is necessary to study the structure of non-linear flyby gravitational scattering using the Rutherford’ formula and to construct the corresponding effective modelling using according regularized phase beams. It is shown that with using of such approach, it is possible to significantly increase the efficiency of the recurrent procedure for the gravity assists chains searching for ballistic scenarios of the modern interplanetary flights.

Statistical Reliability Analysis of Interplanetary Spacecraft Operating at Different Interplanetary Extremity

Reliability of the spacecraft determines the extent of success probability and mission accomplishment. Despite effective testing and integration, the complexity of the space environment affects reliability. In this paper, we investigate the reliability behaviour of interplanetary spacecraft operating at different interplanetary extremities. So, our investigation assesses spacecraft inhered in interplanetary space with the context of the interplanetary boundary (between distinct planetary orbit or within the bounds of heliopause). From the perspective of spacecraft reliability in interplanetary space, we have excluded planetary landers, atmospheric probes, and satellites maneuvering earth orbit. Thus, we have identified 131 spacecraft (includes 82 probes within the bounds of Sun and the Earth, and 49 within the bounds of Earth and Heliopause) along with their gross mass at launch and lifespan. Based on acquired data, we first conduct a non-parametric analysis of spacecraft reliability to obtain two reliability curves for distinct interplanetary extremity. We then perform a parametric fit (Weibull Distribution) over the data to show the analogy of reliability behaviour. Results showed that the spacecraft operating beyond the extremity of the Earth and the Mars exhibits increased reliability than any other interplanetary extremity. In addition to this, we execute reliability analysis over spacecraft of various mass categories (Small-Medium-Large) to testify the reliability effect interpreted by Dubos in 2010. Finally, we discuss the possible factors and causes accountable for the difference in reliability behaviour concerning the spacecraft design and integration, testing, and constraints in considering spacecraft mass.