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ESA's Jupiter Icy Moons Explorer (JUICE) will provide a detailed investigation of the Jovian system in the 2030s, combining a suite of state-of-the-art instruments with an orbital tour tailored to maximise observing opportunities. We review the Jupiter science enabled by the JUICE mission, building on the legacy of discoveries from the Galileo, Cassini, and Juno missions, alongside ground- and space-based observatories. We focus on remote sensing of the climate, meteorology, and chemistry of the atmosphere and auroras from the cloud-forming weather layer, through the upper troposphere, into the stratosphere and ionosphere. The Jupiter orbital tour provides a wealth of opportunities for atmospheric and auroral science: global perspectives with its near-equatorial and inclined phases, sampling all phase angles from dayside to nightside, and investigating phenomena evolving on timescales from minutes to months. The remote sensing payload spans far-UV spectroscopy (50-210 nm), visible imaging (340-1080 nm), visible/near-infrared spectroscopy (0.49-5.56 μm), and sub-millimetre sounding (near 530-625 GHz and 1067-1275 GHz). This is coupled to radio, stellar, and solar occultation opportunities to explore the atmosphere at high vertical resolution; and radio and plasma wave measurements of electric discharges in the Jovian atmosphere and auroras. Cross-disciplinary scientific investigations enable JUICE to explore coupling processes in giant planet atmospheres, to show how the atmosphere is connected to (i) the deep circulation and composition of the hydrogen-dominated interior; and (ii) to the currents and charged particle environments of the external magnetosphere. JUICE will provide a comprehensive characterisation of the atmosphere and auroras of this archetypal giant planet. [ABSTRACT FROM AUTHOR]

This article describes the relationship between shear Alfvén waves and auroral electron acceleration, with an emphasis on long-period standing waves that correlate with redline auroral arcs in the Earth’s magnetosphere. Discrete auroral arcs were correlated with high-latitude field line resonances in the early 1990’s. The past decade has seen advances in all-sky camera technology improve the detection and categorization of “FLR arcs” and establish them as a distinct population. We review observations of redline arcs and discuss estimates of wave amplitudes, wavelengths perpendicular to the geomagnetic field, and saturation times obtained within the framework of two-fluid theories. The two-fluid theory explains the spatial and temporal evolution of FLR optical signatures, but the estimated parallel electric field strengths are insufficient to accelerate electrons and produce 6300 Å auroral emissions. A kinetic theory of FLRs is necessary since electron bounce motion in long-wavelength standing waves affects the ac conductivity and hence the strength of parallel electric fields. In the kinetic theory, the current-voltage relation comprises a conductivity kernel that is a function of the wave frequency, field line length, electron thermal speed, and the number of electron trajectories nearly parallel to geomagnetic field lines close to the ionosphere. The ensuing nonlocal relationship between wave parallel currents and parallel electric fields provides a feasible explanation of the correlation between long-period field line resonances and redline arcs in the terrestrial magnetosphere. The mirror force and particle trapping in the wave fields of shear Alfvén waves are demonstrated to be important aspects of the kinetics of FLRs. [ABSTRACT FROM AUTHOR]

Jupiter is the source of the strongest planetary radio emissions in the solar system. Variations in these emissions are symptomatic of the dynamics of Jupiter's magnetosphere and some have been directly associated with Jupiter's auroras. The strongest radio emissions are associated with Io's interaction with Jupiter's magnetic field. In addition, plasma waves are thought to play important roles in the acceleration of energetic particles in the magnetosphere, some of which impact Jupiter's upper atmosphere generating the auroras. Since the exploration of Jupiter's polar magnetosphere is a major objective of the Juno mission, it is appropriate that a radio and plasma wave investigation is included in Juno's payload. This paper describes the Waves instrument and the science it is to pursue as part of the Juno mission. [ABSTRACT FROM AUTHOR]

Magnetohydrodynamic (MHD) oscillatory processes in different plasma systems, such as the corona of the Sun and the Earth's magnetosphere, show interesting similarities and differences, which so far received little attention and remain under-exploited. The successful commissioning within the past ten years of THEMIS, Hinode, STEREO and SDO spacecraft, in combination with matured analysis of data from earlier spacecraft (Wind, SOHO, ACE, Cluster, TRACE and RHESSI) makes it very timely to survey the breadth of observations giving evidence for MHD oscillatory processes in solar and space plasmas, and state-of-the-art theoretical modelling. The paper reviews several important topics, such as Alfvénic resonances and mode conversion; MHD waveguides, such as the magnetotail, coronal loops, coronal streamers; mechanisms for periodicities produced in energy releases during substorms and solar flares, possibility of Alfvénic resonators along open field lines; possible drivers of MHD waves; diagnostics of plasmas with MHD waves; interaction of MHD waves with partly-ionised boundaries (ionosphere and chromosphere). The review is mainly oriented to specialists in magnetospheric physics and solar physics, but not familiar with specifics of the adjacent research fields. [ABSTRACT FROM AUTHOR]

Shortly after the seminal paper 'Self-Organized Criticality: An explanation of 1/ f noise' by Bak et al. (), the idea has been applied to solar physics, in 'Avalanches and the Distribution of Solar Flares' by Lu and Hamilton (). In the following years, an inspiring cross-fertilization from complexity theory to solar and astrophysics took place, where the SOC concept was initially applied to solar flares, stellar flares, and magnetospheric substorms, and later extended to the radiation belt, the heliosphere, lunar craters, the asteroid belt, the Saturn ring, pulsar glitches, soft X-ray repeaters, blazars, black-hole objects, cosmic rays, and boson clouds. The application of SOC concepts has been performed by numerical cellular automaton simulations, by analytical calculations of statistical (powerlaw-like) distributions based on physical scaling laws, and by observational tests of theoretically predicted size distributions and waiting time distributions. Attempts have been undertaken to import physical models into the numerical SOC toy models, such as the discretization of magneto-hydrodynamics (MHD) processes. The novel applications stimulated also vigorous debates about the discrimination between SOC models, SOC-like, and non-SOC processes, such as phase transitions, turbulence, random-walk diffusion, percolation, branching processes, network theory, chaos theory, fractality, multi-scale, and other complexity phenomena. We review SOC studies from the last 25 years and highlight new trends, open questions, and future challenges, as discussed during two recent ISSI workshops on this theme. [ABSTRACT FROM AUTHOR]

We discuss recent observational, theoretical and numerical progress made in understanding the solar global magnetism and its short and long term variability. We discuss the physical process thought to be at the origin of the solar magnetic field and its 22-yr cycle, namely dynamo action, and the nonlinear interplay between convection, rotation, radiation and magnetic field, yielding modulations of the solar constant or of the large scale flows such as the torsional oscillations. We also discuss the role of the field parity and dynamo families in explaining the complex multipolar structure of the solar global magnetic field. We then present some key MHD processes acting in the deep radiative interior and discuss the probable topology of a primordial field there. Finally we summarize how helioseismology has contributed to these recent advances and how it could contribute to resolving current unsolved problems in solar global dynamics and magnetism. [ABSTRACT FROM AUTHOR]

Unlike most cosmic plasma structures, planetary magnetospheres can be extensively studied in situ. In particular, studies of the Earth's magnetosphere over the past few decades have resulted in a relatively good experimental understanding of both its basic structural properties and its response to changes in the impinging solar wind. In this article we provide a broad overview, designed for researchers unfamiliar with magnetospheric physics, of the main processes and parameters that control the structure and dynamics of planetary magnetospheres, especially the Earth's. In particular, we concentrate on the structure and dynamics of three important regions: the bow shock, the magnetopause and the magnetotail. In the final part of this review we describe the current status of global magnetospheric modelling, which is crucial to placing in situ observations in the proper context and providing a better understanding of magnetospheric structure and dynamics under all possible input conditions. Although the parameter regime experienced in the solar system is limited, the plasma physics that is learned by studying planetary magnetospheres can, in principle, be translated to more general studies of cosmic plasma structures. Conversely, studies of cosmic plasma under a wide range of conditions should be used to understand Earth's magnetosphere under extreme conditions. We conclude the review by discussing this and summarizing some general properties and principles that may be applied to studies of other cosmic plasma structures. [ABSTRACT FROM AUTHOR]

The ionospheric response to auroral precipitation at the giant planets is reviewed, using models and observations. The emission processes for aurorae at radio, infrared, visible, ultraviolet, and X-ray wavelengths are described, and exemplified using ground- and space-based observations. Comparisons between the emissions at different wavelengths are made, where possible, and interpreted in terms of precipitating particle characteristics or atmospheric conditions. Finally, the spatial distributions and dynamics of the various components of the aurorae (moon footprints, low-latitude, main oval, polar) are related to magnetospheric processes and boundaries, using theory, in situ, and remote observations, with the aim of distinguishing between those related to internally-driven dynamics, and those related to the solar wind interaction. [ABSTRACT FROM AUTHOR]

Spacecraft observations have established that all known planets with an internal magnetic field, as part of their interaction with the solar wind, possess well-developed magnetic tails, stretching vast distances on the nightside of the planets. In this review paper we focus on the magnetotails of Mercury, Earth, Jupiter and Saturn, four planets which possess well-developed tails and which have been visited by several spacecraft over the years. The fundamental physical processes of reconnection, convection, and charged particle acceleration are common to the magnetic tails of Mercury, Earth, Jupiter and Saturn. The great differences in solar wind conditions, planetary rotation rates, internal plasma sources, ionospheric properties, and physical dimensions from Mercury's small magnetosphere to the giant magnetospheres of Jupiter and Saturn provide an outstanding opportunity to extend our understanding of the influence of such factors on basic processes. In this review article, we study the four planetary environments of Mercury, Earth, Jupiter and Saturn, comparing their common features and contrasting their unique dynamics. [ABSTRACT FROM AUTHOR]

Mercury's regolith, derived from the crustal bedrock, has been altered by a set of space weathering processes. Before we can interpret crustal composition, it is necessary to understand the nature of these surface alterations. The processes that space weather the surface are the same as those that form Mercury's exosphere (micrometeoroid flux and solar wind interactions) and are moderated by the local space environment and the presence of a global magnetic field. To comprehend how space weathering acts on Mercury's regolith, an understanding is needed of how contributing processes act as an interactive system. As no direct information (e.g., from returned samples) is available about how the system of space weathering affects Mercury's regolith, we use as a basis for comparison the current understanding of these same processes on lunar and asteroidal regoliths as well as laboratory simulations. These comparisons suggest that Mercury's regolith is overturned more frequently (though the characteristic surface time for a grain is unknown even relative to the lunar case), more than an order of magnitude more melt and vapor per unit time and unit area is produced by impact processes than on the Moon (creating a higher glass content via grain coatings and agglutinates), the degree of surface irradiation is comparable to or greater than that on the Moon, and photon irradiation is up to an order of magnitude greater (creating amorphous grain rims, chemically reducing the upper layers of grains to produce nanometer-scale particles of metallic iron, and depleting surface grains in volatile elements and alkali metals). The processes that chemically reduce the surface and produce nanometer-scale particles on Mercury are suggested to be more effective than similar processes on the Moon. Estimated abundances of nanometer-scale particles can account for Mercury's dark surface relative to that of the Moon without requiring macroscopic grains of opaque minerals. The presence of nanometer-scale particles may also account for Mercury's relatively featureless visible-near-infrared reflectance spectra. Characteristics of material returned from asteroid 25143 Itokawa demonstrate that this nanometer-scale material need not be pure iron, raising the possibility that the nanometer-scale material on Mercury may have a composition different from iron metal [such as (Fe,Mg)S]. The expected depletion of volatiles and particularly alkali metals from solar-wind interaction processes are inconsistent with the detection of sodium, potassium, and sulfur within the regolith. One plausible explanation invokes a larger fine fraction (grain size <45 μm) and more radiation-damaged grains than in the lunar surface material to create a regolith that is a more efficient reservoir for these volatiles. By this view the volatile elements detected are present not only within the grain structures, but also as adsorbates within the regolith and deposits on the surfaces of the regolith grains. The comparisons with findings from the Moon and asteroids provide a basis for predicting how compositional modifications induced by space weathering have affected Mercury's surface composition. [ABSTRACT FROM AUTHOR]

The Hermean magnetosphere is likely to contain a number of wave phenomena. We briefly review what little is known so far about fields and waves around Mercury. We further discuss a number of possible phenomena, including ULF pulsations, acceleration-related radiation, bow shock waves, bremsstrahlung (or braking radiation), and synchrotron radiation. Finally, some predictions are made as to the likelihood that some of these types of wave emission exist. [ABSTRACT FROM AUTHOR]

Discusses the existence of collisionless shocks to mediate the flow of supermagnetosonic plasma. Interaction of waves with the ions and electrons; Region of space upstream of the bow shock; Direction of the solar wind magnetic field.

Discusses the formation of magnetosheath between the bow shock and the magnetopause. Contribution of plasma from magnetosphere; Observation of magnetosheath plasma parameters; Nature of the bow shock on the orientation of the interplanetary magnetic field with respect to the local bow shock normal.

The University of California, Berkeley, is the primary science analysis center for the Fast Auroral Snapshot Explorer (FAST). It is responsible for processing and routing the science data to the various investigators and serves as an on-line data archive and science command center for the project. Raw data, received from NASA within a few hours of its transmission to the ground, is processed into CD-ROMs for archive and distribution to the Co-Investigators, and summary data is generated for viewing at the FAST Web site or for retrieval as key parameter data from NASA or the FAST Web site. Daily science command loads and real-time commands are generated to optimize science data collection. This paper presents a description of the FAST ground operations performed at Berkeley. Also included is a discussion of the data analysis software and tools that allow the large data volume (>1 terabyte) to be accessed quickly and efficiently by the scientists. These tasks are more extensive than those performed in the past by science institutions and can be considered as a model for future small programs to reduce cost and maximize science return. [ABSTRACT FROM AUTHOR]