The meteorology of Jupiter's atmosphere

Observations of the atmosphere of Jupiter by the imaging and infrared instruments on the Voyager spacecraft have been analysed to provide new insight into the meteorology of Jupiter. Like the Earth, the atmosphere of Jupiter appears to behave in a quasi-geostrophic manner. For a period prior to the Voyager 1 encounter, the analysis on imaging data indicated that the eddy momentum transfer into the mean zonal flow was a major driving mechanism for the motions. The jet structures are a barotropic phenomena, which the large scale belts and zones depend on for the baroclinicity of the motions and form a family of features. The initial analysis shows that the meteorologies of the Earth and Jupiter have more in common than was previously thought.     

Return to Europa: Overview of the Jupiter Europa orbiter mission

Missions to explore Europa have been imagined ever since the Voyager mission first suggested that Europa was geologically very young. Subsequently, the Galileo spacecraft supplied fascinating new insights into this satellite of Jupiter. Now, an international team is proposing a return to the Jupiter system and Europa with the Europa Jupiter System Mission (EJSM). Currently, NASA and ESA are designing two orbiters that would explore the Jovian system and then each would settle into orbit around one of Jupiter’s icy satellites, Europa and Ganymede. In addition, the Japanese Aerospace eXploration Agency (JAXA) is considering a Jupiter magnetospheric orbiter and the Russian Space Agency is investigating a Europa lander.     

JUXTA: A new probe of X-ray emission from the Jupiter system

For the future Japanese exploration mission of the Jupiter’s magnetosphere (JMO: Jupiter Magnetospheric Orbiter), a unique instrument named JUXTA (Jupiter X-ray Telescope Array) is being developed. It aims at the first in-situ measurement of X-ray emission associated with Jupiter and its neighborhood. Recent observations with Earth-orbiting satellites have revealed various X-ray emission from the Jupiter system. X-ray sources include Jupiter’s aurorae, disk emission, inner radiation belts, the Galilean satellites and the Io plasma torus. X-ray imaging spectroscopy can be a new probe to reveal rotationally driven activities, particle acceleration and Jupiter–satellite binary system. JUXTA is composed of an ultra-light weight X-ray telescope based on micromachining technology and a radiation-hard semiconductor pixel detector. It covers 0.3–2 keV with the energy resolution of <100 eV at 0.6 keV. Because of proximity to Jupiter (∼30 Jovian radii at periapsis), the image resolution of <5 arcmin and the on-axis effective area of >3 cm² at 0.6 keV allow extremely high photon statistics and high resolution observations.     

Current review of the Jupiter, Saturn, and Uranus ionospheres

The ionospheres of the major planets Jupiter, Saturn, and Uranus are reviewed in light of Pioneer and Voyager observations. Some refinements to pre-Voyager theoretical models are required to explain the results, most notably the addition of significant particle ionization from ‛electroglow” and auroral processes and the need for additional chemical loss of protons via charge exchange reactions with water. Water from the Saturn rings has been identified as a major modifier of the Saturn ionosphere and water influx from satellites and/or meteorites may also be important at Jupiter and Uranus as well, as evidenced by the observed ionospheric structure and the identification of cold stratospheric carbon monoxide at Jupiter.     

China's Future Missions for Deep Space Exploration and Exoplanet Space Survey by 2030

Four future missions for deep space exploration and future space-based exoplanet surveys on habitable planets by 2030 are scheduled to be launched. Two Mars exploration missions are designed to investigate geological structure, the material on Martian surface, and retrieve returned samples. The asteroids and main belt comet exploration is expected to explore two objects within 10 years. The small-body mission will aim to land on the asteroid and get samples return to Earth. The basic physical characteristics of the two objects will be obtained through the mission. The exploration of Jupiter system will characterize the environment of Jupiter and the four largest Moons and understand the atmosphere of Jupiter. In addition, we further introduce two space-based exoplanet survey by 2030, Miyin Program and Closeby Habitable Exoplanet Survey (CHES Mission). Miyin program aims to detect habitable exoplanets using interferometry, while CHES mission expects to discover habitable exoplanets orbiting FGK stars within 10 pc through astrometry. The above-mentioned missions are positively to achieve breakthroughs in the field of planetary science.      

Neutral upper atmospheres of the outer planets

Several recent papers have reviewed the upper atmospheres and ionospheres of Jupiter and Saturn in the post Voyager era (see, e.g., /1/ and references therein). Therefore, this paper will review only the most salient characteristics, as far as Jupiter and Saturn are concerned. The emphasis here, however, is placed on the Uranus upper atmosphere that was probed in January, 1986, by Voyager 2 spacecraft. In particular comparative aspects of atmospheric composition, thermal structure, photochemistry and the vertical mixing are discussed.     

NASA历表在深空导航中的发展和比较

利用不同版本的数值历表,对我国正在进行的探月工程以及后续的金星、火星和木星等深空探测中的导航问题进行分析和讨论。对DE405、DE421和DE430的动力学模型及其使用的观测数据进行了分析比较,考察了历表的精度和稳定性。并根据DE430历表简单讨论了木星在我国深空探测站的可视问题,为以后深空导航提供参考。简单讨论了中科院国家天文台行星无线电研究团组基于月球无线电测距(LRR)发展我国自己的历表以及开展基于月球深空导航计划的可行性。     

Radiation analysis for manned missions to the Jupiter system.

An analysis for manned missions targeted to the Jovian system has been performed in the framework of the NASA RASC (Revolutionary Aerospace Systems Concepts) program on Human Exploration beyond Mars. The missions were targeted to the Jupiter satellite Callisto. The mission analysis has been divided into three main phases, namely the interplanetary cruise, the Jupiter orbital insertion, and the surface landing and exploration phases. The interplanetary phase is based on departure from the Earth-Moon L1 point. Interplanetary trajectories based on the use of different propulsion systems have been considered, with resulting overall cruise phase duration varying between two and five years. The Jupiter-approach and the orbital insertion trajectories are considered in detail, with the spacecraft crossing the Jupiter radiation belts and staying around the landing target. In the surface exploration phase the stay on the Callisto surface is considered. The satellite surface composition has been modeled based on the most recent results from the GALILEO spacecraft. In the transport computations the surface backscattering has been duly taken into account. Particle transport has been performed with the HZETRN heavy ion code for hadrons and with an in-house developed transport code for electrons and bremsstrahlung photons. The obtained doses have been compared to dose exposure limits.     

Shoemaker－Levy9彗星撞击木星的流星物理学

本文从流星物理学的基本方程出发,导出Shoemaker-Levy9慧星撞击木星时的速度、质量损失、电子线密度、能量释放率随高度的分布公式;采用合理的参数,作了一系列计算,并与观测资料比较,进行一些讨论。      

The radiation impedance of electrodynamic tethers in a polar Jovian orbit

Juno, the second mission in the NASA New Frontiers Program, will both be a polar Jovian orbiter, and use solar arrays for power, moving away from previous use of radioisotope power systems (RPSs) in spite of the weak solar light reaching Jupiter. The power generation at Jupiter is critical, and a conductive tether could be an alternative source of power. A current-carrying tether orbiting in a magnetized ionosphere/plasmasphere will radiate waves. A magnitude of interest for both power generation and signal emission is the wave impedance. Jupiter has the strongest magnetic field in the Solar Planetary System and its plasma density is low everywhere. This leads to an electron plasma frequency smaller than the electron cyclotron frequency, and a high Alfven velocity. Unlike the low Earth orbit (LEO) case, the electron skin depth and the characteristic size of plasma contactors affect the Alfven impedance.     

屏蔽材料对木星轨道卫星内部介质充电效应的影响研究

在木星轨道的空间辐射环境中,占主导地位的粒子是能量大于1MeV（甚至高于100MeV）的高能电子,这可能会产生卫星内部介质充电效应。在卫星的防辐射设计中,通常需要一定厚度的材料来屏蔽这些电子,使得进入卫星内部的电子通量达到安全的水平。利用所建立的GEANT4-RIC（radiation induced conductivity）方法,研究了运行于木星轨道的卫星对高能电子的最佳屏蔽材料设计。研究了铝、钛、铁、铜、钽和铅作为卫星屏蔽材料的可能性。研究结果表明,在木星探测任务中,为了减轻卫星内部介质充电效应,高原子序数材料比低原子序数材料在相同质量下提供的屏蔽效果更好。因此,用钛、铁、铜、钽或铅代替地球轨道卫星上常用的屏蔽材料铝,可以节省屏蔽质量。     

Force balance in the magnetospheres of Jupiter and Saturn

Spacecraft measurements of the plasma populations and magnetic fields near Jupiter and Saturn have revealed that large magnetospheres surround both planets. Magnetic field measurements have indicated closed field line topologies in the dayside magnetospheres of both planets while plasma instruments have shown these regions to be populated by both hot and cold plasma components convected azimuthally in the sense of planetary rotation. By using published data from the Voyager Plasma Science (PLS), Low Energy Charged Particle (LECP), and Magnetometer (MAG) instruments, it is possible to investigate the validity of the time stationary MHD momentum equation in the middle magnetospheres of Jupiter and Saturn. At Saturn, the hot plasma population is negligible in the dynamic sense and the centrifugal force of the cold rotating plasma appears to balance the Lorentz force. At Jupiter, the centrifugal force balances ～25% of the Lorentz force. The remaining inward Lorentz force is balanced by pressure gradients in the hot, high-β plasma of the Jovian magnetodisk.     

A differential measurement of the Lyman alpha emission from the giant planets using IUE

The intensity of the resonantly scattered Ly-α line of the gian planets depends on the scattering column length of atomic hydrogen above the methane layer and on the incident solar flux. We have obtained measurements of the Ly-α brightness of Jupiter and Saturn on December 19, 1979, with a time difference of 111 minutes, which is only slightly longer than the additional travel time for solar photons scattered at Saturn compared to those from Jupiter. This observational technique eliminates two major uncertainties — the use of different instruments and solar variability — affecting previous determinations of the relative brightness of the planets. The measured ratio of the brightness of the subsolar points is 3.0 ± 0.4 which agrees well with the ratio of the incident solar flux of 3.4. This implies approximately equal scattering column lengths of H on both planets.     

Space telescope studies of Jupiter and Saturn simulated by Voyager observations

Space Telescope (ST) observations of Jupiter and Saturn will offer a unique opportunity for monitoring their changing meteorological characteristics. They will provide higher spatial and temporal resolution for composition and vertical structure studies than have been available to date. We have simulated the planetary camera observations of Jupiter and Saturn by Voyager images of the appropriate spatial scale. With this data set we have investigated the meteorological properties of these atmospheres which can be studied at these scales. In addition we have considered the advances obtainable with the high resolution spectrometer on ST compared with observations from ground-based and other Earth-orbiting satellites. These studies will provide insight into the scientific gain and possible problems in the use of ST for planetary studies.     

Auroral structures at Jupiter and Earth

This paper compares global structures of the aurora observed at Jupiter and Earth and our understanding of the mechanisms that produce these structures. Both planets have permanent, magnetically conjugate auroral ovals, although produced by quite different mechanisms. Both are multispectral, having been observed at X-ray, ultraviolet, visible, infrared, and radio wavelengths. The brightest structures are produced by downward accelerated electron fluxes associated with upward Birkeland (magnetic-field-aligned) currents. At both planets, the auroral forms are time variable, especially at highest latitudes. The main power source for auroral emissions is planetary rotation at Jupiter, and the solar wind interaction at Earth. Thus Jupiter's auroral structures tend to be fixed with respect to magnetic (System III) longitude while Earth's are fixed with respect to local time. Earth's auroral structure is strongly dependent on the direction of the interplanetary magnetic field (IMF). At Jupiter, no IMF dependence is known, but observations have not been sufficient to show such a dependence if it exists. A unique feature of Jupiter's auroral structure, with no counterpart at Earth, is the signature of the large (Galilean) satellites and, in the case of Io, even the corotational wake of the satellite.     

Ultraviolet observations of Jupiter from Earth-orbiting satellites

The International Ultraviolet Explorer (IUE) has provided both improved spectral resolution and some spatial resolution for UV observations of Jupiter. Previous satellite observations have produced albedo curves for Jupiter showing the influence of Rayleigh scattering, and of some absorber(s) shortward of 2500Å on the UV spectrum. Constraints on the abundance of several minor constituents of the Jovian atmosphere were derived from the OAO-2 data. The IUE low dispersion data has a resolution of 8Å, making it possible to detect individual molecular features. A series of C₂H₂ absorptions in the 1750Å region have been identified, and indications of NH₃ absorptions are present in the 1950Å region.     

中国自主木星冰卫星冰下液态海洋探测刍议

木星冰卫星(尤其是"木卫2")在整个太阳系中有非常独特的探测价值,也是当前国际深空探测最前沿、最受关注的领域之一。在对国外相关探测技术归纳总结的同时,结合木星冰卫星冰下海洋探测的若干科学问题,次表层模型、温度廓线及探测深度、电离层的影响等方面,提供了几种木星冰卫星冰下液态水海洋探测的新思路,并给出了一些初步的系统框架设计和次表层介电特性仿真分析等结果。通过对新方法、新模式的探索,有望对我国自主木星冰卫星的次表层液态海洋探测起到良好的借鉴作用。     

太阳电池电路深空探测服役环境与关键技术分析

针对月球、火星、木星等不同的深空探测任务，本文通过在轨服役环境分析，说明了火星探测火星表面光谱计算方法、火星光谱太阳电池设计思路、火星表面除尘技术路线及木星探测低温低光强技术风险。结合工程技术经验，给出了特殊任务应用条件下单片太阳电池推算整板输出功率的计算方法，解决了我国尚无特殊条件的瞬态大太阳模拟器作为整板输出功率测试地面模拟光源的工程难题，为相关科研人员提供参考。     

Energetic ion acceleration and transport in the upstream region of Jupiter: Voyager 1 and 2

Long-lived upstream energetic ion events at Jupiter appear to be very similar in nearly all respects to upstream ion events at earth. A notable difference between the two planetary systems is the enhanced heavy ion compositional signature reported for the Jovian events. This compositional feature has suggested that ions escaping from the Jovian magnetosphere play an important role in forming upstream ion populations at Jupiter. In contrast, models of energetic upstream ions at earth emphasize $\text{in situ}$ acceleration of reflected solar wind ions within the upstream region itself. Using Voyager 1 and 2 energetic (? 30 keV) ion measurements near the magnetopause, in the magnetosheath, and immediately upstream of the bow shock, we examine the compositional patterns together with typical energy spectra in each of these regions. We find characteristic spectral changes late in ion events observed upstream of the bow shock at the same time that heavy ion fluxes are enhanced and energetic electrons are present. A model involving upstream Fermi acceleration early in events and emphasizing energetic particle escape in the prenoon part of the Jovian magnetosphere late in events is presented to explain many of the features in the upstream region of Jupiter.     

木星磁场及磁场模型的对比分析

木星具有太阳系最强的行星磁场,是木星探测面临的基本环境。首先对磁场环境及其数学模型进行了调研,并在研究木星磁场模型以及磁场的数学原理的基础上,使用MATLAB数学工具实现了木星主磁场的计算,对VIP4、VIT4、O6和V1_17ev（eigenvector,特征向量）4个模型与磁测数据进行了对比及分析。研究结果表明这4个模型计算得到的磁场强度范围较为一致,但在全球磁场分布上存在差异,尤其是对磁南极位置的识别上,4个模型的结果都不相同;在对模型计算结果与探测数据的探讨分析中,发现4个模型与探测数据的符合较为一致,偏差均较小。可为木星探测的环境保障提供必要的理论基础和计算模型支撑。