空间辐射场中高能Fe离子微剂量学分析

Fe离子是空间辐射场中备受关注的重离子之一,其等效剂量、生物效应等构成载人航天的主要危险。文章通过计算等效组织正比计数器对高能Fe离子的响应,模拟其在等效组织中的线能微剂量学量。计算得到的结果与实验结果基本符合,偏差不超过10%;在此基础上,考虑TEPC(组织等效正比计数器)对银河宇宙射线中能量范围在90～1000 MeV/u的Fe离子的响应,得到其线能量为80～600keV/μm,最大值在100～150keV/μm之间;通过公式计算得到100～200keV/μm线能量对应的射线品质因数高于25,将产生相当高的生物效应。     

The reflection model for propagation of solar cosmic rays

The principles of constructing the model are considered in this paper, together with the issues of its components and physical algorithm. The main emphasis is placed on the cause-and-effect relationships between the structure and dynamics of the solar and interplanetary media and the motion of solar cosmic ray particles. The specific features of the initial phase of motion of the particles after their acceleration in a solar flare are considered, as well as the subsequent phase of further particle propagation in the solar corona, and the phase of motion in the heliosphere. The processes of transport of charged particles in flare plasma ejections are considered in detail.     

Galactic cosmic rays and parameters of the interplanetary medium near solar activity minima

The time behavior of intensity of cosmic rays with relatively low (~1–6 GeV) and high (>10 GeV) energies are considered together with characteristics influencing the modulation of cosmic rays in the heliosphere. The periods under study are close to solar activity minima in cycles 21/22, 22/23, and 23/24. Diffusion and convection in small-scale magnetic fields of the heliosphere are demonstrated to play some role only at sufficiently weak disturbances of the field (B/δB > 1.3). In this case, a negative correlation is observed between B/δB and a tilt of the surface of the heliospheric current sheet. The analysis of characteristics of the interplanetary medium in periods of solar activity minima shows that the energy anomaly of cosmic rays in the minimum of cycles 23/24 is caused by deficit of high energy particles rather than by an excess of particles of relatively small energies.     

Detection of ultrahigh-energy cosmic rays and neutrinos by radio method using artificial lunar satellites

An estimate of the feasibility of the ultrahigh-energy cosmic ray and neutrino detection using a lunar satellite-borne radio receiver is presented. The data obtained in the proposed experiment will make resolving the current contradictions in the ultrahigh-energy cosmic ray spectra measured with the major ground-based instruments possible. Moreover, they will enable us to considerably extend the accessible energy range and to check predictions of various models of the origin of the highest-energy particles in the Universe. At the same time the lunar radio detector provides a means of searching for ultrahigh-energy neutrinos with a high sensitivity combined with a very large target effective mass.     

Acceleration of solar cosmic rays and the fine spectral structure of type II radio bursts

On the basis of data, obtained by means of the ground-based solar service RSTN (Radio Solar Telescope Network) and the geostationary satellite system GOES, the relationship between the solar cosmic rays (SCR) intensity I _p with the proton energy E _p > 1 MeV and parameters of meter-decameter type II radio bursts in the frequency range of 25–180 MHz is studied. The process of proton acceleration by shock waves was characterized by the frequency drift velocity of radio bursts V _mII and the relative difference between radio emission frequencies at the first two harmonics b. It is shown that the coefficient of correlation between I _p and b increases with E _p growing from 0.40 to 0.70, while a similar coefficient between I _p and V _mII does not exceed 0.30. Indications in favor of the two-stage SCR acceleration model are obtained.     

Respective role of microgravity and cosmic rays on Paramecium tetraurelia cultured aboard Salyut 6.

Paramecium tetraurelia cultured aboard Salyut 6 have shown in increase in cell growth rate, cell volume, water content and changes in electrolyte content. Additional experiments, carried out in balloon flight and on earth, showed that the stimulating effect observed on cell proliferation is related to exposure to cosmic rays. Other changes seem to be due to a direct effect of microgravity on cell. Mechanism of gravity action on cell is discussed.     

Energy measurements of electrons and protons in cosmic ray physics using satellite and balloon calorimeters in recent two decades

Calorimeters are used in cosmic ray studies for a variety of purposes, such as measurements of particle energy, separation of electrons and hadrons, formation of triggers (signals for activation of instruments), and so on. In this review we consider the methods of energy reconstruct of protons and electrons (for particles with energies exceeding 10 GeV) in calorimeters of various types that are used in astrophysical experiments of cosmic ray studies carried out with balloons and satellites.     

On the relationship between quasi-biennial variations of solar activity,the heliospheric magnetic field and cosmic rays

Quasi-biennial oscillations (QBO) of solar activity (T ≈ 1–4 years) are considered to be a variation of basic solar activity, associated with the solar dynamo process. They are transferred into interplanetary space by the open magnetic flux of the Sun, generating QBO in the intensity of cosmic rays (CR). This paper discusses the observational characteristics of QBO in CR and their relationship with QBO on the Sun and in the interplanetary medium. The delay time of QBO in CR relative to the solar and heliospheric magnetic field suggests that the formation of QBO in the open magnetic flux of the Sun occurs within 3–5 months. The paper considers the question of the prominent periodicity of CR (T = 1.6 years) that has prevailed in CR and in the heliospheric magnetic field for more than 10 years but was not stable over 60 years of observations. Distinctions in the characteristics of QBO and long-term variations of CR suggest features of the mechanism of their formation.     

On the possibility of existence of an additional source of anomalous cosmic rays outside the solar system

On the basis of experimental data obtained at exposure of solid-state track detectors in the magnetosphere of the Earth during solar flares and in quiet Sun periods, an estimate of possible contribution of singly charged oxygen ions to the flare particle fluxes is made. A possibility is considered of the appearance in the vicinity of the solar system of singly ionized oxygen ions generated on stars.     

An analysis of peculiarities of the satellite autonomous navigation in sighting unknown landmarks on the planet surface

An analysis of characteristics of autonomous navigation by using optical sighting of unknown landmarks was carried out for artificial satellites in circular orbits around the Earth with altitudes from 300 to 900 km. It is shown that navigational errors vary approximately in inverse proportion to duration of measurements. Also they decrease with an increasing number of sighted landmarks. The errors poorly depend on the orbit altitude if the duration of measurement for each landmark is chosen in proportion to the orbit altitude, or a maximal zenith angle of sighting the landmark remains constant.Some characteristics of the navigational algorithm are given. Admissible deviations of initial orbital elements from their exact values are investigated. For a properly chosen measurement procedure the algorithm proves to be stable even for rather crudely given initial parameters.     

Instability of entropy waves in cosmic plasma

A dispersion equation is derived for small disturbances of the magnetohydrodynamic type in optically transparent plasma with cosmic abundance of elements. The electron heat conductivity along the magnetic field and proton heat conductivity across the field are taken into account. It is shown that entropy waves increase exponentially in wide ranges of temperatures and densities of the cosmic plasma. Manifestations of instability of the entropy waves in the cosmic plasma are discussed.     

基于小孔成像技术的中能电子成像谱仪及其空间观测结果

中能电子测量对空间辐射环境的理论研究和空间航天器的防护设计具有重要意义。北京大学研制的中能电子成像谱仪（BD-IES）利用小孔成像技术实现多方向中能电子的能谱测量。地面标定试验结果表明,BD-IES具有良好的能量线性度和较小的系统噪声,能够有效实现对中能电子的能谱测量。该仪器已成功应用在我国导航卫星上。最新测量结果表明BD-IES对中能电子的测量是成功的,其结果对于研究如亚暴注入、波-粒子相互作用等空间物理热点问题具有重要意义。BD-IES未来将被应用到“风云”等空间环境探测平台上。     

Geochronology and monitoring of cosmic rays for accumulating cosmogenic isotopes <Superscript>53</Superscript>Mn and <Superscript>10</Superscript>Be in terrestrial rocks

The paper is devoted to discussing the method of measuring the accumulation of radioactive isotopes ⁵³Mn (with a half-life T = 3.7 million years) and ¹⁰Be (T = 2.5 million years) in iron-bearing rocks. Knowledge of the dynamics of the accumulation of these isotopes would allow us to estimate the variations in the intensity of cosmic rays, periods of glaciations and geological changes, as well as climatic processes on the Earth in retrospect of 0.1–10 million years. For an operative study of a large number of samples, it has been proposed to use a low-cost neutron activation method with the implementation of the ⁵³Mn(n, γ)⁵⁴Mn reaction in a slow neutron reactor. As has been shown, using the 10Be isotope together with ⁵³Mn makes it possible to simultaneously determine both the cosmic-ray fluxes and the shielding time of the corresponding region from cosmic radiation. To obtain the reliable data on cosmic rays, it has been proposed to study rock samples from the lunar surface.     

SETI in the light of cosmic convergent evolution

Theodosius Dobzhansky, one of the founding fathers of the modern evolutionary synthesis, once famously stated that “nothing makes sense in biology except in the light of evolution”. Here it will be argued that nothing in astrobiology makes sense except in the light of “Cosmic Convergent Evolution” (CCE). This view of life contends that natural selection is a universal force of nature that leads to the emergence of similarly adapted life forms in analogous planetary biospheres. Although SETI historically preceded the rise of astrobiology that we have witnessed in the recent decade, one of its main tenets from the beginning was the convergence of life on a cosmic scale toward intelligent behavior and subsequent communication via technological means. The question of cultural convergence in terms of symbolic exchange, language and scientific capabilities between advanced interstellar civilizations has been the subject of ongoing debate. However, at the core of the search for extraterrestrial intelligence lies in essence a biological problem since even post-biological extraterrestrial intelligences must have had an origin based on self-replicating biopolymers. Thus, SETI assumes a propensity of the Universe towards biogenesis in accordance with CCE, a new evolutionary concept which posits the multiple emergence of life across the Cosmos. Consequently, we have to wonder about the biophilic properties the Universe apparently exhibits, as well as to try to find an encompassing theory that is able to explain this “fine-tuning” in naturalistic terms. The aims of this paper are as follows: 1) to emphasize the importance of convergent evolution in astrobiology and ongoing SETI research; 2) to introduce novel and biology-centered cosmological ideas such as the “Selfish Biocosm Hypothesis” and the “Evo Devo Universe” as valuable arguments in theorizing about the origin and nature of extraterrestrial intelligence and 3) to synthesize these findings within an emerging post-biological paradigm on which future SETI efforts may be founded.     

一种考虑自动驾驶仪动态特性的自适应变结构制导律

对于平面拦截问题，提出了一种新的具有强鲁棒性的末端导引规律。将目标的机动加速度视为一类有界扰动，以视线角速率作为零输出状态变量，考虑导弹自动驾驶仪动态特性，应用滑模趋近律概念，综合设计了一种自适应变结构制导律。理论分析与数字仿真表明这种制导律不但具有优良的弹道特性，而且具有很强的鲁棒性和适应性，同时方法简单、易于理解，便于工程应用。     

Some peculiarities of changes in characteristics of proper atmosphere of space objects

We consider the behavior of the proper atmosphere of space objects in interaction with a flow of incident particles and when the orientation of an object changes. An asymmetry in the behavior of a sorption film with respect to an incident flow of atmospheric particles and the flow’s angular characteristics is shown, as well as the film influence on operation of sensors of the spacecraft’s attitude control system. A recommendation concerning usage of heavy gases for technological operations onboard spacecraft is given.     

Short-term variation of cosmic ray diurnal anisotropy and solar activity

A correlative analysis has been made between cosmic ray intensity and solar activity (sunspot numbers) during high amplitude days for the period 1991–1995. The high amplitude days with the time of maximum in the corotational/azimuthal direction do not indicate any significant correlation with solar activity. The diurnal amplitude significantly remains constant and high (0.5%) during the entire period. Our observations suggest that the direction of the anisotropy of high amplitude anisotropic wave train events contribute significantly to the short-term behavior of the cosmic ray diurnal anisotropy. The correlation coefficient is found to remain positive during solar activity maximum for all the high amplitude anisotropic wave train events.