Magnetised Wave Collapse in Solar System Plasmas

AbstractClumpy, intense wave packets observed in situ in the Jovian and terrestrial electron foreshocks, and in the Earth’s auroral acceleration zone, point to the existence of non-linear plasma turbulence in these regions. In non-linear turbulence, wave packets collapse to short scales and high fields, stopping only when coherent wave-particle interactions efficiently dissipate the energy in the waves. The purpose of this paper is to examine the shortest scales and highest fields achieved during collapse in a strongly magnetised plasma, and identify parts of the solar system where the magnetised aspects of wave collapse are important.

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Laboratory and in-situ analysis of comet dust

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100102122 ◽

1988 ◽

Vol 46 ◽

pp. 8-9

Author(s):

D.E. Brownlee ◽

A.L. Albee

Keyword(s):

Electron Microscopy ◽

Solar System ◽

Laboratory Study ◽

Isotopic Analysis ◽

Building Blocks ◽

Sem Analysis ◽

Early Solar System ◽

Cometary Material ◽

Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

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Interferometric (Fourier-Spectroscopic) Measurement of Electron Energy Distributions

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134144 ◽

1990 ◽

Vol 48 (2) ◽

pp. 110-111 ◽

Cited By ~ 1

Author(s):

F. Hasselbach ◽

A. Schäfer

Keyword(s):

Group Velocity ◽

Wave Packets ◽

Index Of Refraction ◽

Electron Wave ◽

Fringe Contrast ◽

Faraday Cage ◽

Optical Index ◽

Wien Filter ◽

Coherent Wave ◽

Electric And Magnetic Fields

Möllenstedt and Wohland proposed in 1980 two methods for measuring the coherence lengths of electron wave packets interferometrically by observing interference fringe contrast in dependence on the longitudinal shift of the wave packets. In both cases an electron beam is split by an electron optical biprism into two coherent wave packets, and subsequently both packets travel part of their way to the interference plane in regions of different electric potential, either in a Faraday cage (Fig. 1a) or in a Wien filter (crossed electric and magnetic fields, Fig. 1b). In the Faraday cage the phase and group velocity of the upper beam (Fig.1a) is retarded or accelerated according to the cage potential. In the Wien filter the group velocity of both beams varies with its excitation while the phase velocity remains unchanged. The phase of the electron wave is not affected at all in the compensated state of the Wien filter since the electron optical index of refraction in this state equals 1 inside and outside of the Wien filter.

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In Situ exploration of the giant planets

Experimental Astronomy ◽

10.1007/s10686-021-09775-z ◽

2021 ◽

Author(s):

O. Mousis ◽

D. H. Atkinson ◽

R. Ambrosi ◽

S. Atreya ◽

D. Banfield ◽

...

Keyword(s):

Solar System ◽

Giant Planets ◽

Atmospheric Composition ◽

Formation History ◽

History Of ◽

Composition Structure ◽

Galileo Probe ◽

Probe Measurements

AbstractRemote sensing observations suffer significant limitations when used to study the bulk atmospheric composition of the giant planets of our Solar System. This impacts our knowledge of the formation of these planets and the physics of their atmospheres. A remarkable example of the superiority of in situ probe measurements was illustrated by the exploration of Jupiter, where key measurements such as the determination of the noble gases’ abundances and the precise measurement of the helium mixing ratio were only made available through in situ measurements by the Galileo probe. Here we describe the main scientific goals to be addressed by the future in situ exploration of Saturn, Uranus, and Neptune, placing the Galileo probe exploration of Jupiter in a broader context. An atmospheric entry probe targeting the 10-bar level would yield insight into two broad themes: i) the formation history of the giant planets and that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. An atmospheric probe could represent a significant ESA contribution to a future NASA New Frontiers or flagship mission to be launched toward Saturn, Uranus, and/or Neptune.

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Non-linear plasma wave decay to longer wavelength

10.1063/1.4923104 ◽

2015 ◽

Cited By ~ 3

Author(s):

F. Anderegg ◽

M. Affolter ◽

A. Ashourvan ◽

D. H. E. Dubin ◽

F. Valentini ◽

...

Keyword(s):

Plasma Wave ◽

Wave Decay ◽

Non Linear ◽

Linear Plasma

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Non-linear partial least square regression increases the estimation accuracy of grass nitrogen and phosphorus using in situ hyperspectral and environmental data

ISPRS Journal of Photogrammetry and Remote Sensing ◽

10.1016/j.isprsjprs.2013.04.012 ◽

2013 ◽

Vol 82 ◽

pp. 27-40 ◽

Cited By ~ 54

Author(s):

A. Ramoelo ◽

A.K. Skidmore ◽

M.A. Cho ◽

R. Mathieu ◽

I.M.A. Heitkönig ◽

...

Keyword(s):

Partial Least Square ◽

Least Square ◽

Environmental Data ◽

Partial Least Square Regression ◽

Estimation Accuracy ◽

Nitrogen And Phosphorus ◽

Least Square Regression ◽

Non Linear

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Solar System Exploration Augmented by In-Situ Resource Utilization: Mercury and Saturn Propulsion Investigations

8th Symposium on Space Resource Utilization ◽

10.2514/6.2016-0717 ◽

2016 ◽

Cited By ~ 1

Author(s):

Bryan A. Palaszewski

Keyword(s):

Solar System ◽

Resource Utilization ◽

Solar System Exploration

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Linear and non-linear potential-flow calculations of free-surface waves with lift and induced drag

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/0954406001523795 ◽

2000 ◽

Vol 214 (6) ◽

pp. 801-812

Author(s):

C-E Janson

Keyword(s):

Free Surface ◽

Potential Flow ◽

Lift Force ◽

Radiation Condition ◽

Linear Potential ◽

Surface Boundary ◽

Model Approximation ◽

Non Linear ◽

Lifting Surfaces ◽

The Waves

A potential-flow panel method is used to compute the waves and the lift force from surface-piercing and submerged bodies. In particular the interaction between the waves and the lift produced close to the free surface is studied. Both linear and non-linear free-surface boundary conditions are considered. The potential-flow method is of Rankine-source type using raised source panels on the free surface and a four-point upwind operator to compute the velocity derivatives and to enforce the radiation condition. The lift force is introduced as a dipole distribution on the lifting surfaces and on the trailing wake, together with a flow tangency condition at the trailing edge of the lifting surface. Different approximations for the spanwise circulation distribution at the free surface were tested for a surface-piercing wing and it was concluded that a double-model approximation should be used for low speeds while a single-model, which allows for a vortex at the free surface, was preferred at higher speeds. The lift force and waves from three surface-piercing wings, a hydrofoil and a sailing yacht were computed and compared with measurements and good agreement was obtained.

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Terrestrial aurora: astrophysical laboratory for anomalous abundances in stellar systems

Annales Geophysicae ◽

10.5194/angeo-32-77-2014 ◽

2014 ◽

Vol 32 (2) ◽

pp. 77-82 ◽

Cited By ~ 1

Author(s):

I. Roth

Keyword(s):

Solar Flares ◽

Heavy Ions ◽

Electromagnetic Waves ◽

Stellar System ◽

Decay Product ◽

Early Solar System ◽

Physical Processes ◽

In Situ Observations ◽

The Waves

Abstract. The unique magnetic structure of the terrestrial aurora as a conduit of information between the ionosphere and magnetosphere can be utilized as a laboratory for physical processes at similar magnetic configurations and applied to various evolutionary phases of the solar (stellar) system. The most spectacular heliospheric abundance enhancement involves the 3He isotope and selective heavy elements in impulsive solar flares. In situ observations of electromagnetic waves on active aurora are extrapolated to flaring corona in an analysis of solar acceleration processes of 3He, the only element that may resonate strongly with the waves, as well as heavy ions with specific charge-to-mass ratios, which may resonate weaker via their higher gyroharmonics. These results are applied to two observed anomalous astrophysical abundances: (1) enhanced abundance of 3He and possibly 13C in the late stellar evolutionary stages of planetary nebulae; and (2) enhanced abundance of the observed fossil element 26Mg in meteorites as a decay product of radioactive 26Al isotope due to interaction with the flare-energized 3He in the early solar system.

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