Worst‐Case Severe Environments for Surface Charging observed at LANL satellites as Dependent on Solar Wind and Geomagnetic Conditions

Abstract. It is important to appreciate how the morphology of internal charging of spacecraft systems, due to penetrating electrons, differs from that of the more common surface charging, due to electrons with lower energy. A specific and recurrent anomaly on a geostationary communication satellite has been tracked for ten years so that solar cycle and seasonal dependencies can be clearly established. Concurrent measurements of sunspot number, solar wind speed and 2-day >2 MeV electron fluence are presented to highlight pertinent space weather relationships, and the importance of understanding the complex particle interaction processes involved.Key words. Magnetospheric physics (energetic particles; trapped; solar wind – magnetosphere interactions) – space plasma physics (spacecraft sheaths, wakes, charging)

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Spacecraft surface charging induced by severe environments at geosynchronous orbit

Space Weather ◽

10.1002/2017sw001689 ◽

2018 ◽

Vol 16 (1) ◽

pp. 89-106 ◽

Cited By ~ 18

Author(s):

J.-C. Matéo-Vélez ◽

A. Sicard ◽

D. Payan ◽

N. Ganushkina ◽

N. P. Meredith ◽

...

Keyword(s):

Geosynchronous Orbit ◽

Surface Charging ◽

Severe Environments

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Role of the surface charging in the solar wind interaction with a small, non-magnetized, electrically non-conducting body studied in a two-dimensional electromagnetic full particle simulation

2011 XXXth URSI General Assembly and Scientific Symposium ◽

10.1109/ursigass.2011.6051095 ◽

2011 ◽

Author(s):

Tomoko Nakagawa

Keyword(s):

Solar Wind ◽

Particle Simulation ◽

Two Dimensional ◽

Solar Wind Interaction ◽

Surface Charging ◽

Conducting Body

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Orbit limited theory in the solar wind - κ distributions

Serbian Astronomical Journal ◽

10.2298/saj160220004m ◽

2016 ◽

pp. 27-34 ◽

Cited By ~ 1

Author(s):

M.M. Martinovic

Keyword(s):

Solar Wind ◽

Electrostatic Potential ◽

Collisionless Plasma ◽

Velocity Distribution Function ◽

Plasma Sheath ◽

Plasma Velocity ◽

Solid Object ◽

Ionized Gas ◽

Surface Charging ◽

Font Color

When a solid object is immersed into ionized gas it gets brought to a certain value of electrostatic potential and surrounded by a space charge region called ?plasma sheath?. Through this region, particles are attracted or repelled from the surface of the charge collecting object. For collisionless plasma, this process is described by the so-called orbit limited theory, which explains how the collection of particles is determined by the collector geometry and plasma velocity distribution function (VDF). In this article, we provide explicit expressions for orbit-limited currents for generalized Lorentzian (?) distributions. This work is useful to describe the charging processes of objects in non-collisional plasmas like the solar wind, where the electrons VDF is often observed to exhibit quasi power-law populations of suprathermal particles. It is found that these ?suprathermals? considerably increase the charge collection. Since the surface charging process that determines the value of electrostatic potential is also affected by the plasma VDF, calculation of the collector potential in the solar wind is described along with some quantitative predictions. [Projekat Ministarstva nauke Republike Srbije, br. 176002] This article has been corrected. Link to the correction <a href="http://dx.doi.org/10.2298/SAJ1795071E">10.2298/SAJ1795071E</a>

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Realistic Worst Case for a Severe Space Weather Event Driven by a Fast Solar Wind Stream

Space Weather ◽

10.1029/2018sw001948 ◽

2018 ◽

Vol 16 (9) ◽

pp. 1202-1215 ◽

Cited By ~ 8

Author(s):

Richard B. Horne ◽

Mark W. Phillips ◽

Sarah A. Glauert ◽

Nigel P. Meredith ◽

Alex D. P. Hands ◽

...

Keyword(s):

Solar Wind ◽

Space Weather ◽

Solar Wind Stream ◽

Fast Solar Wind ◽

Weather Event ◽

Worst Case ◽

Event Driven ◽

Space Weather Event

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Dependence of lunar surface charging on solar wind plasma conditions and solar irradiation

Planetary and Space Science ◽

10.1016/j.pss.2013.07.008 ◽

2014 ◽

Vol 90 ◽

pp. 10-27 ◽

Cited By ~ 32

Author(s):

T.J. Stubbs ◽

W.M. Farrell ◽

J.S. Halekas ◽

J.K. Burchill ◽

M.R. Collier ◽

...

Keyword(s):

Solar Wind ◽

Lunar Surface ◽

Solar Wind Plasma ◽

Solar Irradiation ◽

Surface Charging

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Spacecraft Worst Case Surface Charging: On the Importance of Measuring the Electron Emission Yield Under Representative Environmental Conditions

IEEE Transactions on Plasma Science ◽

10.1109/tps.2019.2925435 ◽

2019 ◽

Vol 47 (8) ◽

pp. 3790-3795 ◽

Cited By ~ 1

Author(s):

J.-C. Mateo-Velez ◽

M. Belhaj ◽

S. Dadouch ◽

P. Sarrailh ◽

S. L. G. Hess ◽

...

Keyword(s):

Electron Emission ◽

Environmental Conditions ◽

Worst Case ◽

Surface Charging ◽

Emission Yield

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

International Astronomical Union Colloquium ◽

10.1017/s0252921100101666 ◽

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.

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Mosaic Mapping: A Means of Tiling Images to Shorten Acquisition Speed for Lower - Magnification SEM Images and Wavelength Dispersive Spectrometers (WDS) X-Ray Maps

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100164659 ◽

1996 ◽

Vol 54 ◽

pp. 438-439

Author(s):

J.D. Geller ◽

C.R. Herrington

Keyword(s):

Limiting Factors ◽

X Rays ◽

Angular Range ◽

Acceptance Angle ◽

Sem Images ◽

Worst Case ◽

X Ray ◽

Focusing Distance ◽

Layered Crystals ◽

Working Distance

The minimum magnification for which an image can be acquired is determined by the design and implementation of the electron optical column and the scanning and display electronics. It is also a function of the working distance and, possibly, the accelerating voltage. For secondary and backscattered electron images there are usually no other limiting factors. However, for x-ray maps there are further considerations. The energy-dispersive x-ray spectrometers (EDS) have a much larger solid angle of detection that for WDS. They also do not suffer from Bragg’s Law focusing effects which limit the angular range and focusing distance from the diffracting crystal. In practical terms EDS maps can be acquired at the lowest magnification of the SEM, assuming the collimator does not cutoff the x-ray signal. For WDS the focusing properties of the crystal limits the angular range of acceptance of the incident x-radiation. The range is dependent upon the 2d spacing of the crystal, with the acceptance angle increasing with 2d spacing. The natural line width of the x-ray also plays a role. For the metal layered crystals used to diffract soft x-rays, such as Be - O, the minimum magnification is approximately 100X. In the worst case, for the LEF crystal which diffracts Ti - Zn, ˜1000X is the minimum.

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