scholarly journals Solar wind control of Jovian auroral emissions

2005 ◽  
Vol 110 (A9) ◽  
Author(s):  
Patrick H. M. Galopeau ◽  
Mohammed Y. Boudjada
Keyword(s):  
Solar Wind ◽  
Auroral Emissions

Characteristics of the solar wind controlled auroral emissions

1998 ◽  
Vol 103 (A8) ◽  
pp. 17543-17557 ◽  
Author(s):  
K. Liou ◽  
P. T. Newell ◽  
C.-I. Meng ◽  
M. Brittnacher ◽  
G. Parks
Keyword(s):  
Solar Wind ◽  
Auroral Emissions

scholarly journals Jupiter’s Aurora: Solar Wind and Rotational Influences

2002 ◽  
Vol 12 ◽  
pp. 606
Author(s):  
J. Hunter Waite ◽  
John T. Clarke ◽  
R.J. Walker ◽  
John E.P. Connerney ◽  
D. McComas ◽  
...  
Keyword(s):  
Solar Wind ◽  
Electric Fields ◽  
Strong Field ◽  
Heavy Ion ◽  
Loss Cone ◽  
X Ray ◽  
Planetary Rotation ◽  
Angle Scattering ◽  
Auroral Emissions ◽  
Atmospheric Loss

AbstractJovian auroral emissions are observed at infrared, visible, ultraviolet, and x-ray wavelengths. As at Earth, pitch-angle scattering of energetic particles into the atmospheric loss cone and the acceleration of current-carrying electrons in field-aligned currents both play a role in exciting the auroral emissions. The x-ray aurora is believed to result principally from heavy ion precipitation, while the ultraviolet aurora is produced predominantly by precipitating energetic electrons. The magnetospheric processes responsible for the aurora are driven primarily by planetary rotation. Acceleration of Iogenic plasma by rotationally-induced electric fields results in both the formation of the energetic ions that are scattered and the formation of strong, field-aligned currents that communicate the torques from the ionosphere. In addition to rotation-driven processes, solar-wind-modulated processes in the outer magnetosphere may lead to highly, time-dependent acceleration and thus also contribute to jovian auroral activity. Observational evidence for both sources will be presented. See Waite et al. (2001, Nat., 410, 787).

Magnetosphere–Ionosphere Coupling

2021 ◽  
Author(s):  
N. Achilleos ◽  
L. C. Ray ◽  
J. N. Yates
Keyword(s):  
Solar Wind ◽  
Electrical Current ◽  
Auroral Oval ◽  
Upper Atmosphere ◽  
Space Environment ◽  
Rotating Disc ◽  
Field Lines ◽  
Auroral Emissions ◽  
Rapid Rotator ◽  
Energy And Momentum

The process of magnetosphere-ionosphere coupling involves the transport of vast quantities of energy and momentum between a magnetized planet and its space environment, or magnetosphere. This transport involves extended, global sheets of electrical current, which flows along magnetic field lines. Some of the charged particles, which carry this current rain down onto the planet’s upper atmosphere and excite aurorae–beautiful displays of light close to the magnetic poles, which are an important signature of the physics of the coupling process. The Earth, Jupiter, and Saturn all have magnetospheres, but the detailed physical origin of their auroral emissions differs from planet to planet. The Earth’s aurora is principally driven by the interaction of its magnetosphere with the upstream solar wind—a flow of plasma continually emanating from the Sun. This interaction imposes a particular pattern of flow on the plasma within the magnetosphere, which in turn determines the morphology and intensity of the currents and aurorae. Jupiter, on the other hand, is a giant rapid rotator, whose main auroral oval is thought to arise from the transport of angular momentum between the upper atmosphere and the rotating, disc-like plasma in the magnetosphere. Saturn exhibits auroral behavior consistent with a solar wind–related mechanism, but there is also regular variability in Saturn’s auroral emissions, which is consistent with rotating current systems that transport energy between the magnetospheric plasma and localized vortices of flow in the upper atmosphere/ionosphere.

scholarly journals Auroral emissions from Uranus and Neptune

2020 ◽  
Vol 378 (2187) ◽  
pp. 20190481 ◽  
Author(s):  
L. Lamy
Keyword(s):  
Solar Wind ◽  
Hubble Space Telescope ◽  
Current Knowledge ◽  
Rotation Period ◽  
Magnetic Field Rotation ◽  
Planetary Rotation ◽  
Voyager 2 ◽  
Depth Study ◽  
Auroral Emissions

Uranus and Neptune possess highly tilted/offset magnetic fields whose interaction with the solar wind shapes unique twin asymmetric, highly dynamical, magnetospheres. These radiate complex auroral emissions, both reminiscent of those observed at the other planets and unique to the ice giants, which have been detected at radio and ultraviolet (UV) wavelengths to date. Our current knowledge of these radiations, which probe fundamental planetary properties (magnetic field, rotation period, magnetospheric processes, etc.), still mostly relies on Voyager 2 radio, UV and in situ measurements, when the spacecraft flew by each planet in the 1980s. These pioneering observations were, however, limited in time and sampled specific solar wind/magnetosphere configurations, which significantly vary at various timescales down to a fraction of a planetary rotation. Since then, despite repeated Earth-based observations at similar and other wavelengths, only the Uranian UV aurorae have been re-observed at scarce occasions by the Hubble Space Telescope. These observations revealed auroral features radically different from those seen by Voyager 2, diagnosing yet another solar wind/magnetosphere configuration. Perspectives for the in-depth study of the Uranian and Neptunian auroral processes, with implications for exoplanets, include follow-up remote Earth-based observations and future orbital exploration of one or both ice giant planetary systems. This article is part of a discussion meeting issue ‘Future exploration of ice giant systems’.

Norwegian-Canadian Svalbard Expedition, winter 1975

Polar Record ◽  
1976 ◽  
Vol 18 (113) ◽  
pp. 171-173
Author(s):  
F. T. Berkey ◽  
O. E. Harang
Keyword(s):  
Solar Wind ◽  
Low Energy ◽  
Direct Access ◽  
Polar Ionosphere ◽  
Energy Particle ◽  
Photometric Observations ◽  
Aircraft Observations ◽  
Land Mass ◽  
Auroral Emissions ◽  
Limited Duration

Current theories and observations in magnetospheric physics suggest that low-energy particle fluxes, exhibiting the characteristics of solar-wind particles, have direct access to certain regions of the high-latitude polar ionosphere (Akasofu and Lanzerotti, 1975). The precipitation of these particles occurs over a few degrees of latitude and several hours of magnetic time (centred on geomagnetic noon) and this region has been termed the dayside magnetospheric cleft (Vasyliunas, 1974). The resultant phenomena, such as dayside auroral emissions, have not been extensively studied due to the rather remote location of accessible land mass at latitudes high enough for observations at local apparent noon to be made (Fig 1). Magnetospheric cleft observations have been carried out from instrumental aircraft (Whalen and Pike, 1973) and from Cape Parry, NWT (Peterson and Shepherd, 1974) in previous winters. Aircraft observations are, obviously, of limited duration and twilight at Cape Parry severely restricts photometric observations.

Saturn's E, G and F rings: modulated by the plasma sheet

1984 ◽  
Vol 75 ◽  
pp. 597
Author(s):  
E. Grün ◽  
G.E. Morfill ◽  
T.V. Johnson ◽  
G.H. Schwehm
Keyword(s):  
Solar Wind ◽  
Direct Contact ◽  
Transport Processes ◽  
Time Variable ◽  
Dust Particles ◽  
Spatial Diffusion ◽  
Drag Forces ◽  
Orbit Perturbation ◽  
Time Variations ◽  
F Ring

ABSTRACTSaturn's broad E ring, the narrow G ring and the structured and apparently time variable F ring(s), contain many micron and sub-micron sized particles, which make up the “visible” component. These rings (or ring systems) are in direct contact with magnetospheric plasma. Fluctuations in the plasma density and/or mean energy, due to magnetospheric and solar wind processes, may induce stochastic charge variations on the dust particles, which in turn lead to an orbit perturbation and spatial diffusion. It is suggested that the extent of the E ring and the braided, kinky structure of certain portions of the F rings as well as possible time variations are a result of plasma induced electromagnetic perturbations and drag forces. The G ring, in this scenario, requires some form of shepherding and should be akin to the F ring in structure. Sputtering of micron-sized dust particles in the E ring by magnetospheric ions yields lifetimes of 102to 104years. This effect as well as the plasma induced transport processes require an active source for the E ring, probably Enceladus.

Quantitative surface damage studies by H.R.E.M.

1989 ◽  
Vol 47 ◽  
pp. 632-633
Author(s):  
S. R. Singh ◽  
H. J. Fan ◽  
L. D. Marks
Keyword(s):  
Solar Wind ◽  
Quantitative Analysis ◽  
Surface Science ◽  
Surface Damage ◽  
Space Environment ◽  
Oxygen Desorption ◽  
The Past ◽  
Diffusion Controlled ◽  
Original Observation ◽  
Substantial Interest

Since the original observation that the surfaces of materials undergo radiation damage in the electron microscope similar to that observed by more conventional surface science techniques there has been substantial interest in understanding these phenomena in more detail; for a review see. For instance, surface damage in a microscope mimics damage in the space environment due to the solar wind and electron beam lithographic operations.However, purely qualitative experiments that have been done in the past are inadequate. In addition, many experiments performed in conventional microscopes may be inaccurate. What is needed is careful quantitative analysis including comparisons of the behavior in UHV versus that in a conventional microscope. In this paper we will present results of quantitative analysis which clearly demonstrate that the phenomena of importance are diffusion controlled; more detailed presentations of the data have been published elsewhere.As an illustration of the results, Figure 1 shows a plot of the shrinkage of a single, roughly spherical particle of WO3 versus time (dose) driven by oxygen desorption from the surface.

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