Magnetospheric Science Objectives of the <Emphasis Type="Italic">Juno</Emphasis> Mission

In July 2016, NASA’s Juno mission becomes the first spacecraft to enter polar orbit of Jupiter and venture deep into unexplored polar territories of the magnetosphere. Focusing on these polar regions, we review current understanding of the structure and dynamics of the magnetosphere and summarize the outstanding issues. The Juno mission profile involves (a) a several-week approach from the dawn side of Jupiter’s magnetosphere, with an orbit-insertion maneuver on July 6, 2016; (b) a 107-day capture orbit, also on the dawn flank; and (c) a series of thirty 11-day science orbits with the spacecraft flying over Jupiter’s poles and ducking under the radiation belts. We show how Juno’s view of the magnetosphere evolves over the year of science orbits. The Juno spacecraft carries a range of instruments that take particles and fields measurements, remote sensing observations of auroral emissions at UV, visible, IR and radio wavelengths, and detect microwave emission from Jupiter’s radiation belts. We summarize how these Juno measurements address issues of auroral processes, microphysical plasma physics, ionosphere-magnetosphere and satellite-magnetosphere coupling, sources and sinks of plasma, the radiation belts, and the dynamics of the outer magnetosphere. To reach Jupiter, the Juno spacecraft passed close to the Earth on October 9, 2013, gaining the necessary energy to get to Jupiter. The Earth flyby provided an opportunity to test Juno’s instrumentation as well as take scientific data in the terrestrial magnetosphere, in conjunction with ground-based and Earth-orbiting assets.     

Grain Surface Models and Data for Astrochemistry

The cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of \({\sim}25\) experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions.     

Designing corrections for the trajectory of the <Emphasis Type="Italic">Spektr-R</Emphasis> spacecraft in the event of immersions into the Moon’s sphere of influence

The results of updating the parameters of motion of the Spektr-R spacecraft at the end of 2016 have shown that, in January 2018, with a probability close to unity, the condition that a spacecraft stay in the Earth’s shadow is violated; however, in May of the same year, the ballistic life of the spacecraft will be terminated. Thus, in 2017, the question arose of how to design the correction of flight of this spacecraft using its onboard propulsion system. The correction was designed with allowance for the fact that, for the first time since it was launched, the spacecraft in the course of several years, beginning with 2017, repeatedly approaches the Moon, deeply immersing into its sphere of influence. This paper presents the technologically and organizationally convenient, allowable versions of upcoming correction of the Spektr-R spacecraft trajectory and justifies the particular scheme of its implementation.     

Longitudinal dependence of the H<Superscript>+</Superscript> concentration distribution in the plasmasphere according to <Emphasis Type="Italic">INTERBALL-1</Emphasis> satellite data

The paper has presented a study of the dependence of the H⁺ ions concentration in the plasmasphere on geographic longitude. A vast database of measurements of the cold plasma density by the Alpha-3 instrument on board the INTERBALL-1 satellite has been used for the study. Based on these measurements, a dependence of the H⁺ ions concentration in the filled magnetic flux tube in the plasmasphere in the equatorial plane under quiet geomagnetic conditions has been obtained as a function of geographic longitude. Studies have been performed for two seasons, summer and winter. It has been shown that, during the summer in the near-midnight sector, the minimum in the H⁺ concentration falls within geographic longitudes of 270°–315°. The ratio of the concentration of H⁺ ions at various longitudes could reach a factor of three. During the winter, in the near-noon sector, the maximum of the H⁺ ions concentration falls within longitudes of 180°–225°, whereas the concentration ratio could reach a factor of 2.2.     

Dynamics of electron fluxes in the slot between radiation belts in November–December 2014 according to data of the <Emphasis Type="Italic">Vernov</Emphasis> satellite

The variations in the spatial structure and time in electron fluxes with E = 235–300 keV in the slot region (2 < L < 3) between the radiation belts in the period of November 1, 2014 through December 8, 2014 during weak and moderate geomagnetic disturbances (Kp < 4, Dst >–60 nT) are analyzed based on the data of the RELEC complex on board the Vernov satellite (the height and inclination of the orbit are from 640 to 830 km and 98.4°, respectively). Irregular increases in the fluxes of such electrons and formation of a local maximum at L ~ 2.2–3.0 were observed. It has been shown that the intensity of this maximum is inversely proportional to the L value and grows with an increase in the geomagnetic activity level. New features discovered for the first time in the dynamics of radiation belt electrons manifest in the variations in the local structure and dynamics of fluxes of subrelativistic electrons in the slot region.     

Study of the magnetospheres of active regions on the sun by radio astronomy techniques

In the 1990s, based on detailed studies of the structure of active regions (AR), the concept of the magnetosphere of the active region was proposed. This includes almost all known structures presented in the active region, ranging from the radio granulation up to noise storms, the radiation of which manifests on the radio waves. The magnetosphere concept, which, from a common point of view, considers the manifestations of the radio emission of the active region as a single active complex, allows one to shed light on the relation between stable and active processes and their interrelations. It is especially important to identify the basic ways of transforming nonthermal energy into thermal energy. A dominant role in all processes is attributed to the magnetic field, the measurement of which on the coronal levels can be performed by radio-astronomical techniques. The extension of the wavelength range and the introduction of new tools and advanced modeling capabilities makes it possible to analyze the physical properties of plasma structures in the AR magnetosphere and to evaluate the coronal magnetic fields at the levels of the chromosphere–corona transition zone and the lower corona. The features and characteristics of the transition region from the S component to the B component have been estimated.     

双馈型风电系统变流器控制参数对振荡模态的影响

研究双馈型风力发电系统变流器控制参数对振荡模态的影响。在MATLAB/Simulink中建立系统详细的小信号模型,利用特征值分析和相关因子分析,对机网相互作用振荡模态进行辨识和分类。通过改变变流器控制参数,研究振荡模态的变化特性。最后,在MATLAB/Simulink上进行仿真验证。研究表明,优化变流器控制参数,可有效抑制振荡。     

基于变刚度特性的轴流压气机叶型重构方法研究

为能准确预估轴流压气机叶片在工作状态下的形状,基于流固耦合迭代策略,考虑离心力和气动力对叶片变形的作用,发展了一种适用于轴流压气机的叶型重构方法。在构型转化过程中,计入了叶片受力载荷随叶型变化的非线性效应以及叶片的变刚度特性。采用叶片变形后状态的受力载荷与刚度矩阵计算叶片节点位移,反复迭代修正热态叶片形状,最终获得满足精度要求的热态叶型数据。利用所提出的方法,对Stage 37的转子叶片进行了叶型重构,经20步迭代计算可获得最大残差小于10-4mm量级的热态叶型,通过与试验数据的对比分析,验证了重构算法的可靠性和工程实用性。     

Time-dependent cosmic ray modulation

Time-dependent cosmic ray modulation is calculated over multiple solar cycles using our well established two-dimensional time-dependent modulation model. Results are compared to Voyager 1, Ulysses and IMP cosmic ray observations to establish compatibility. A time-dependence in the diffusion and drift coefficients, implicitly contained in recent expressions derived by , ,  and , is incorporated into the cosmic ray modulation model. This results in calculations which are compatible with spacecraft observations on a global scale over consecutive solar cycles. This approach compares well to the successful compound approach of Ferreira and Potgieter (2004). For both these approaches the magnetic field magnitude, variance of the field and current sheet tilt angle values observed at Earth are transported time-dependently into the outer heliosphere. However, when results are compared to observations for extreme solar maximum, the computed step-like modulation is not as pronounced as observed. This indicates that some additional merging of these structures into more pronounced modulation barriers along the way is needed.