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Plasma Science, IEEE Transactions on

Issue 2 • Date Feb. 2012

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  • Table of contents

    Publication Year: 2012 , Page(s): C1 - 137
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  • IEEE Transactions on Plasma Science publication information

    Publication Year: 2012 , Page(s): C2
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  • Special Issue on Spacecraft Charging Technology 2012

    Publication Year: 2012 , Page(s): 138
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    The 32 papers in this special issue were originally presented at the 11th Spacecraft Charging Technology Conference. held in Albuquerque, NM, in September 2010. View full abstract»

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  • New Frontiers in Spacecraft Charging

    Publication Year: 2012 , Page(s): 139 - 143
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (372 KB) |  | HTML iconHTML  

    Spacecraft charging, as a field, is continually being recharged by new developments in understanding, new materials and technologies, and new approaches to both new and old problems. I will discuss some of the new frontiers in understanding spacecraft charging in this paper, as well as referencing relevant papers from the 11th Spacecraft Charging Technology Conference. Spacecraft charging is highly material-property dependent. For example, the secondary electron emission, photoemission, bulk electrical resistivity, and surface resistivity are important parameters that help determine the extent of spacecraft charging (both on the surface and inside the spacecraft) in any given environment. Our understanding of these material properties is one of the new frontiers in spacecraft charging. I will discuss how these fundamental material properties have been found to depend on the following: proper measurement techniques, temperature, radiation flux, electric field, surface treatment, surface contamination from plumes and outgassing, surface modification through arcing and vacuum exposure, and synergistic effects. Modeling of spacecraft charging is a second new frontier. New developments in modeling have both improved our understanding of spacecraft charging and enabled us to model situations that are dynamic and geometrically complex. New schemes for treating both space and time variations of fields, particle fluxes, and spectra have made our modeling more precise and accurate. Now, many more spacecraft are being launched into low Earth orbit and the radiation belts. Modeling charging effects more accurately in those orbits will become more important than ever. A third new frontier in spacecraft charging is novel mitigation techniques. Surface materials and simple passive devices that emit electrons as fast as they are collected seem to make real-time charge mitigation cheaply and reliably achievable for the first time. Novel solar cell configurations and coverglass mate- ials promise to make arcing, both of the primary electrostatic discharge (ESD) type and sustained arcing between cells or strings, a thing of the past. Superconducting cables may obviate the high voltages that lead to arcing. New cooperation between spacecraft and solar array manufacturers and spacecraft charging experts may help to prevent the spacecraft charging mistakes of the past. Furthermore, the final frontier is dealing with new materials and higher power requirements. Lightweight spacecraft materials are, in some cases, prone to exacerbate charging or arcing and may allow transmission of electromagnetic interference into sensitive electronics. New solar cell active materials may increase the effects of arcing on solar cell and solar array performance, even for primary ESD events. Higher power requirements may require longer transmission cables, which may increase the need for higher voltages, making arcing more likely. If superconducting cables become a reality, magnetics may become very important for spacecraft control and stability. What will happen to a superconducting cable if it must carry the increased current in an arcing event of very short duration? View full abstract»

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  • The Jovian Charging Environment and Its Effects—A Review

    Publication Year: 2012 , Page(s): 144 - 154
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1610 KB) |  | HTML iconHTML  

    Several space missions are being considered for Jupiter. These range from the recently launched Juno mission to possible joint NASA and ESA missions to Europa and Ganymede. Although the direct effects of radiation dose are normally considered the most pressing design issue for these missions, spacecraft charging, through surface charging, vxB, and, more importantly, internal charging, is also a key design concern. This paper reviews the current state of understanding of the jovian charging environment including the background plasma, high-energy electrons, and magnetic field. In conjunction with these environments, we will also review the range of effects to be expected in response to these environments. These effects need to be carefully considered in parallel with radiation effects in the design of the planned missions if they are to survive in the extremely challenging jovian environment. View full abstract»

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  • Plasma Analyzer for Measuring Spacecraft Floating Potential in LEO and GEO

    Publication Year: 2012 , Page(s): 155 - 166
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    A design for a plasma analyzer for measuring spacecraft floating potential is described. The proposed Plasma Analyzer for Space Science (PASS) would use two methods simultaneously to determine spacecraft charge. Floating potential to kilovolts negative may be determined by the energy analysis of positively charged particles (ions) through the low energy ion cutoff method. Floating potentials from a few tens of volts negative to the highest positive potentials expected may be measured though the electron-spectroscopic method. The use of two charge-sensing techniques should allow a large range of both positive and negative floating potentials to be measured. The simultaneous use of two dissimilar methods enables the refinement of both methods and should improve the reliability of spacecraft floating potential measurement. PASS should be able to determine spacecraft floating potential in both low Earth orbit and geosynchronous Earth orbit from -10 kV to the largest positive floating potential expected. Based on what was learned from the development of the Spacecraft Charge Monitor, PASS should have superior performance in energy resolution, geometric factor, and data-gathering efficiency compared to charged particle energy analyzers that have been used in the past. View full abstract»

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  • A Review of Mechanisms and Models Accounting for Surface Potential Decay

    Publication Year: 2012 , Page(s): 167 - 176
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (613 KB) |  | HTML iconHTML  

    We present here a wide review of the existing models accounting for surface potential decay, developed in various areas of electrostatics. Several polarization or transport processes may be involved. Though most of the models initially stemmed from electrostatics and semiconductor physics, around the notion of mobility, experiments on polymers often require “thermodynamic” models, describing progressive charge detrapping. Different physical processes likely to be involved in the potential decay (dipolar relaxation, induced conductivity, dispersive transport, slow detrapping) can lead in disordered materials to the same time response, the challenge being to design inventive procedures to distinguish them. A particular attention will be given to the application of these models to polyimide and fluorinated ethylene propylene. The specific case of radiation-induced conductivity in these materials will also be examined in detail. View full abstract»

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  • SPIS and MUSCAT Software Comparison on LEO-Like Environment

    Publication Year: 2012 , Page(s): 177 - 182
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (942 KB) |  | HTML iconHTML  

    Two spacecraft charging software tools, the Spacecraft Plasma Interaction Software and the Multi-Utility Spacecraft Charging Analysis Tool, have been compared in the situation of a wake generated by an object immersed in dense drifting plasma. Each model takes account of the particle dynamics, the space charge effect on the electric field, and the currents collected by the object. The cross-comparison resulted in a good agreement between the two codes and with previous experiments conducted on the same configuration. In particular, a highly negative voltage imposed to the object rear side allows the collection of drifting ions at this location. The nontrivial shape of the current density map was correctly simulated by the two codes. Future works may allow to reach a better quantitative agreement. View full abstract»

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  • SPIS Multitimescale and Multiphysics Capabilities: Development and Application to GEO Charging and Flashover Modeling

    Publication Year: 2012 , Page(s): 183 - 191
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1556 KB) |  | HTML iconHTML  

    While it demonstrated its capability to simulate many common situations, Spacecraft Plasma Interaction Software (SPIS) open source code lacked the possibility to model more challenging situations. The major cases of interest were identified as related to either multitimescale or multiphysical situations. Two major improvements were brought to SPIS code to answer these needs. The first one was an implicit circuit solver with an automatic determination of time steps. The implemented Newton-type algorithm makes use of a predictor for the plasma current variations when surface potentials change. The second major development was a multiphysical model for electrons. The approach consisted in using equilibrium or dynamical electron models in two different zones and connecting these zones at their boundary through a Child-Langmuir (CL)-type condition. Fulfilling this condition dynamically determines the location of the boundary and the electron current to be injected from the dense thermal zone to the space-charge zone. These new features were then used to simulate validation and application cases. The first one consisted in modeling a charging situation in GEO, which had been modeled with NASA charging analyzer (NASCAP) codes and published. Concerning the multiphysical model of electrons, the loop controlling the CL condition was first tested on elementary cases, exhibiting a good qualitative and quantitative behavior. It was then applied to the modeling of a ground experiment performed in JONAS plasma tank at the Office National d'Etudes et Recherches Aérospatiales, i.e., the expansion of the flashover generated by an electrostatic discharge over a precharged solar array coupon, leading to its neutralization. View full abstract»

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  • Current and Voltage Thresholds for Sustained Arcs in Power Systems

    Publication Year: 2012 , Page(s): 192 - 200
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1297 KB) |  | HTML iconHTML  

    In the late 1990s, satellites began to suffer multiple solar cell string failures, prematurely ending the satellite mission due to insufficient power. The root cause was determined to be sustained vacuum arcs triggered by electrostatic discharge, which in turn was caused by solar array charging in the ambient environment. The satellite industry reacted to the failures by adopting laboratory charging tests of solar array coupons as part of design qualification. Gradually over the decade since, researchers in industry, academia, and national laboratories have roughly delineated the current and voltage levels that put solar arrays at risk for sustained arcing. That decade of test results has reconfirmed what was previously established by the power industry research on vacuum arcs in the 1950s to 1980s: that sustained vacuum arcs are not possible at typical array string currents. However, conditions for sustained arcing exist in the solar array harness beyond the cathodes of the string blocking diodes where string currents are combined and routed to the main spacecraft power bus. Qualification tests should therefore focus on the array backside and harness, where the current levels are sufficient, and should include current sources representative of the main spacecraft power bus. View full abstract»

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  • Is There a Largest ESD Event?

    Publication Year: 2012 , Page(s): 201 - 208
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (712 KB) |  | HTML iconHTML  

    Ground-based electron charging tests are commonly performed as part of satellite design qualification. The objective of the test is to determine the severity of the resulting electrostatic discharges (ESD) and, via subsequent analysis, determine the hazard they pose to the health and function of the satellite. ESD tests generate large data sets because of the substantial and random variation in ESD amplitudes. The variability is readily apparent in time series scatter plots. The average amplitude, the range of amplitudes (standard deviation), and a worst case event in a set of data are immediately seen. If a failure threshold is known, the margin between that threshold and both the average and worst case events can be shown. Common practice is to compare either the worst case observed event or a 3-sigma upper limit to the failure threshold when assessing the risk of ESD-induced failure. Several samples of ESD test data are reviewed, and the cumulative probability distributions are shown to follow a power law relationship. Applying a Gaussian distribution to the data implies failure is nearly impossible, whereas the power law shows failure is certain because the power law has fatter tails in the extreme event end of the distribution. The consequences of fat tails for ESD risk assessment are discussed. View full abstract»

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  • Photoemission Driven Charging in Tenuous Plasma

    Publication Year: 2012 , Page(s): 209 - 216
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (809 KB) |  | HTML iconHTML  

    In the cold, tenuous plasma commonly encountered in magnetospheric and interplanetary orbits, and in the case of scientific satellites with nearly all surfaces effectively conducting, surface charging is driven by photoemission current. The differential potential of the few insulating surfaces, such as lenses or insulating grout between solar cells, can be positive or negative depending on the photoemissivity of the material. We analyze this effect for spacecraft like those of the Magnetospheric MultiScale and the Radiation Belt Storm Probes missions. This paper develops a simple theory for the potentials of sunlit insulators, focusing on insulators that make up a small part of a large conductive surface. The shape of the photoemission spectrum places an absolute limit of about 12 V of positive differential charging on sunlit insulators. For small insulating surfaces, the conventional assumption-that the photoelectronsthat cannot energetically escape return to their surface of origin-is not valid because the photoelectron trajectory path length is large compared with the surface dimension. We describe a theory that accounts for photoelectron transport between small insulators and the surrounding conductive area. These calculations are done both for the case that the insulator has photoemission similar to the conductive area and for the case that the photoemission is far less, as is the case for many insulators. If the insulator has photoemission current density similar to that of a conductor, we predict positive differential potentials of about 2 V at low chassis potential and negligible differential at high chassis potential. In the opposite case that the insulator photoemission is low, we predict no differential at low chassis potentials and negative differential potentials of up to several volts at high chassis potential. View full abstract»

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  • PTetra, a Tool to Simulate Low Orbit Satellite–Plasma Interaction

    Publication Year: 2012 , Page(s): 217 - 229
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (322 KB) |  | HTML iconHTML  

    A model is presented to numerically simulate the time-dependent interaction of satellites with space plasma. The approach is based on a fully kinetic description of the plasma using particle in cell modeling for all plasma species with physical charges and masses. The model also relies on a discretization of space with an unstructured tetrahedral mesh that is capable of representing complex boundaries and realistic spacecraft geometries. The code solves for the self-consistent electric fields, given calculated volume charges and charge deposition on the various satellite components. The model is purely electrostatic, but it does account for the effects of a possible constant and uniform background magnetic field. View full abstract»

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  • Electron–Ion Coupling in Mesothermal Plasma Beam Emission: Full Particle PIC Simulations

    Publication Year: 2012 , Page(s): 230 - 236
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (885 KB) |  | HTML iconHTML  

    Full particle particle-in-cell simulations are performed to study the collisionless electron-ion coupling during ion beam emission and neutralization. Simulations show that ion beam neutralization and propagation are two closely coupled processes. Electron-ion coupling is achieved through interactions between the trapped electrons and a potential well established by the propagation of the ion beam front along the beam direction and not through plasma instabilities as previous studies suggested. In the transverse direction, the beam emission generates an expansion fan similar to that of the expansion of a mesothermal plasma into vacuum. The expansion process determines the beam potential with respect to the ambient. This suggests that a plasma beam in a vacuum chamber and a plasma beam in space may have similar charge density profiles but different beam potentials with respect to the ambient due to the limit imposed by the boundary on plasma expansion. View full abstract»

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  • The Timescale of Surface-Charging Events

    Publication Year: 2012 , Page(s): 237 - 245
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1256 KB) |  | HTML iconHTML  

    The timescale for creating high potentials on shadowed spacecraft surfaces depends on the conductivity of the surface in question, whether the neighboring surfaces are tied to the spacecraft frame or not, and on the space environment input. It is understood from laboratory and spaceflight measurements that the likelihood of a large surface potential and the timescale over which it might occur depends on these variables, yet the complex interplay between them makes the hazard difficult to assess even in controlled experiments. In this paper, we approach the specific question of the timescale of surface charging using several data sets in several orbit regimes: geostationary orbit (GEO), highly elliptical orbit (HEO), and low-Earth orbit (LEO). The measurements that we will show involve different approaches to the question of surface charging and subsequent electrostatic discharge (ESD) (GEO: surface charge monitors; HEO: direct plasma measurements; LEO: anomalies due to surface charging). However, the main strengths of the data are derived from their long duration covering multiple years and their occasional overlap in time. Here, we report on the timescale of surface-charging events at different locations in the magnetosphere across ~11 years of geomagnetic activity. The results will be relevant for assessments of space system impacts due to surface discharges and ESD, simulations of surface charging, and laboratory testing of flight system designs. View full abstract»

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  • Conceptual Design and Assessment of an Electrostatic Discharge and Flashover Detector on Spacecraft Solar Panels

    Publication Year: 2012 , Page(s): 246 - 253
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (927 KB) |  | HTML iconHTML  

    This paper presents a concept of monitor aiming at measuring the electrostatic discharge (ESD) occurrence and, possibly, a flashover expansion on spacecraft photovoltaic solar panels. The passive measurement of solar cell cover glass surface potential is used as a diagnostic. The monitor consists of small metallic plates located on the sunlit solar panel. With a sufficient electrical insulation from the spacecraft structure, these plates float to the same potential as the surrounding cover glasses. The photoemission is the physical phenomenon allowing the homogenization of the local surface potentials. Theoretical, numerical, and experimental investigations are used to assess how well such a device could record the evolution of the solar panel surface voltage. Combined with a dedicated measurement chain and telemetry, ESD occurrences could thus be measured on in-flight solar panels. View full abstract»

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  • Charge-Enhanced Contamination and Environmental Degradation of MISSE-6 SUSpECS Materials

    Publication Year: 2012 , Page(s): 254 - 261
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1012 KB) |  | HTML iconHTML  

    The effects of prolonged exposure to the low Earth orbit space environment and charge-enhanced contamination on optical, thermal, and electron emission and transport properties of common spacecraft materials have been investigated by comparing pre- and postflight characterization measurements. The State of Utah Space Environment and Contamination Study (SUSpECS), deployed in March 2008 on board the Materials International Space Station Experiment (MISSE-6) payload, was exposed for ~18 months on the exterior of the International Space Station (ISS) and was retrieved in September 2009. A total of 165 samples was mounted on three separate SUSpECS panels on the ram and wake sides on the ISS. Some samples, particularly those exposed to atomic oxygen in the ram direction, showed pronounced effects due to exposure. Biased samples for the charge-enhanced contamination study showed subtle variations in visible and infrared reflectivity. View full abstract»

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  • Surface-Charging Analysis of the Radiation Belt Storm Probe and Magnetospheric MultiScale Spacecraft

    Publication Year: 2012 , Page(s): 262 - 273
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1601 KB) |  | HTML iconHTML  

    The Radiation Belt Storm Probes (RBSPs) are a pair of satellites to be launched in 2012 into 500 × 30 600 km 10°-inclination orbits. The Magnetospheric MultiScale (MMS) mission spacecraft are a set of four satellites to be launched in 2014 into 1300 × 70 000 km (1.2 × 12 Re) 28 °-inclination orbits. The apogee will be boosted to 150 000 km (25 Re) during the mission. The spacecraft of both missions will measure magnetic and electric fields and the charged-particle distribution. As measurements of low-energy plasma and of electric fields are sensitive to surface potentials, stringent requirements for electrostatic cleanliness are imposed on both spacecraft designs. We present a surface-charging analysis of the RBSP and MMS spacecraft designs. The resulting chassis and differential potentials are used to estimate spacecraft-generated effects on the measurements and the risk of arcing. View full abstract»

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  • A Proposed Two-Stage Two-Tether Scientific Mission at Jupiter

    Publication Year: 2012 , Page(s): 274 - 281
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (638 KB) |  | HTML iconHTML  

    A two-stage mission to place a spacecraft (SC) below the Jovian radiation belts, using a spinning bare tether with plasma contactors at both ends to provide propulsion and power, is proposed. Capture by Lorentz drag on the tether, at the periapsis of a barely hyperbolic equatorial orbit, is followed by a sequence of orbits at near-constant periapsis, drag finally bringing the SC down to a circular orbit below the halo ring. Although increasing both tether heating and bowing, retrograde motion can substantially reduce accumulated dose as compared with prograde motion, at equal tether-to-SC mass ratio. In the second stage, the tether is cut to a segment one order of magnitude smaller, with a single plasma contactor, making the SC to slowly spiral inward over several months while generating large onboard power, which would allow multiple scientific applications, including in situ study of Jovian grains, auroral sounding of upper atmosphere, and space- and time-resolved observations of surface and subsurface. View full abstract»

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  • Secondary Electron Emission on Space Materials: Evaluation of the Total Secondary Electron Yield From Surface Potential Measurements

    Publication Year: 2012 , Page(s): 282 - 290
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1316 KB) |  | HTML iconHTML  

    Secondary electron emission (SEE) is one of the main parameters controlling spacecraft potential. It also plays an important role in the triggering of the multipactor phenomenon occurring in waveguides (electron avalanche in microwave electric fields). In this paper, we propose an original method adapted to low-energy SEE measurements on dielectrics and conductors (incident electron energy below 20 eV). It is based on Kelvin probe (KP) surface potential measurements after electron irradiation. It is particularly well suited to insulating materials but can also be used on metals by letting the sample potential float. We present results of SEE measurements performed on metals used in waveguides, Kapton, Teflon, and CMX cover glass. In order to avoid any experimental artifact due to the earth magnetic field and conduct accurate low-energy measurements with the KP method, the distance between the electron gun and the sample is chosen to be negligible compared to the Larmor radius. View full abstract»

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  • Approximation of Range in Materials as a Function of Incident Electron Energy

    Publication Year: 2012 , Page(s): 291 - 297
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1465 KB) |  | HTML iconHTML  

    A simple composite analytic expression has been developed to approximate the electron range in materials. The expression is applicable over more than six orders of magnitude in energy (<; 10 eV to >; MeV) and range ( 10-9-10-2 m), with an uncertainty of ≤ 20% for most conducting, semiconducting, and insulating materials. This is accomplished by fitting data from two standard NIST databases [ESTAR for the higher energy range and the electron inelastic mean free path (IMFP) for the lower energies]. In turn, these data have been fit with well-established semiempirical models for range and IMFP that are related to standard material properties (e.g., density, atomic number, atomic weight, stoichiometry, and bandgap energy). Simple relations between the IMFP and the range, based on the continuous-slow-down approximation, are used to merge results from the two databases into a composite range expression. A single free parameter, termed the effective number of valence electrons per atom Nv, is used to predict the range over the entire energy span. View full abstract»

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  • Measurement Methods of Electron Emission Over a Full Range of Sample Charging

    Publication Year: 2012 , Page(s): 298 - 304
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (741 KB) |  | HTML iconHTML  

    Spacecraft charging codes require accurate models of electron yields as a function of accumulated charge to correctly predict the charge buildup on spacecraft. The accumulated charge creates equilibrium surface potentials on spacecraft resulting from interactions with the space plasma environment. There is, however, a complex relation between these emission properties and the charge built up in spacecraft insulators. This paper focuses on different methods appropriate to determine the fundamental electronic material property of the total electron yield as the materials accumulate charge. Three methods for determining the uncharged total yield are presented: 1) The dc continuous beam method is a relatively easy and accurate method appropriate for conductors and semiconductors with maximum total electron yield σmax <; 2 and resistivity ρ <; 1017 Ω·cm; 2) the pulsed-yield method seeks to minimize the effects of charging and is applicable to materials with σmax <; 4 and ρ up to >; 1024 Ω·cm; and 3) the yield decay method is a very difficult and time-consuming technique that uses a combination of measurement and modeling to investigate the most difficult materials with σmax >; 4 and ρ up to <; 1024 Ω·cm. Data for high-purity polycrystalline Au, Kapton HN and CP1 polyimides, and polycrystalline aluminum oxide ceramic are presented. These data demonstrate the relative strengths and weaknesses of each method but more importantly show that the methods described herein are capable of reliably measuring the total electron yield of almost any spacecraft material. View full abstract»

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  • The Effects of Surface Modification on Spacecraft Charging Parameters

    Publication Year: 2012 , Page(s): 305 - 310
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (656 KB) |  | HTML iconHTML  

    Charging of materials by incident radiation is affected by both environmental and physical conditions. Modifying a material's physical surface will change its reflection, transmission, and absorption of the incident radiation which are integrally related to the accumulation of charge and energy deposition in the material. General arguments for incident and emitted photons, electrons, and ions are considered. An optical analysis of the effects of surface modification on spacecraft charging parameters on prototypical polyimide Kapton HN and Cu samples is presented. Samples were roughened with abrasive compounds ranging from 0.5 to 10 μm in size, comparable to the range of incident wavelengths. They were also contaminated with thin layers of DC 704 diffusion pump oil. Using a UV/VIS/NIR light source and a diffraction grating spectrometer, measurements were performed on pristine and modified materials. The measured spectra confirmed that surface modifications induce expected changes in optical reflection, transmission, and absorption. The generally increased absorption observed results in increased photon energy deposited in the material, leading to increased charge emission through the photoelectric effect. View full abstract»

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  • Parametric Study of a Physical Flashover Simulator

    Publication Year: 2012 , Page(s): 311 - 320
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1464 KB) |  | HTML iconHTML  

    A physical flashover (FO) simulator has been developed by ONERA/DESP and CNES. The objective of this simulator is to represent the missing cells when testing small coupons in the laboratory. The aim of this paper is to present the results of a parametric study which has been performed on a sample constituted by a solar-array coupon made of six cells and a simulator constituted of a large surface of metallized polymeric film. Experiments were performed in the ONERA/DESP facility called JONAS which is a 9-m3 vacuum chamber equipped with a plasma source and a 10-keV electron gun. Electrostatic discharges (ESDs) occur in the inverted potential gradient (IPG) configuration obtained either by electrons or by plasma. The FO was characterized by measuring the neutralization current on the different surfaces with current probes. Therefore, we could get charge quantity, duration, and velocity. The surface potential of the coupon and the polymeric film were monitored before and after ESD by a potential probe, giving a good correlation with the amount of charges participating to the discharge. In order to determine what the limits of the FO are and what parameters can monitor it, we have studied different configurations: 1) electron or plasma IPG charging; 2) surfaces from 0.5 to 14 m2; 3) geometries-cylinder, ring, rectangular, and discontinuous surface; 4) primary arc locations-cell edge or interconnectors; and 5) absolute satellite capacitance values-between 300 pF and 300 nF. Analysis of the results is given for these configurations. View full abstract»

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  • Development of Flashover Current Simulator for ESD Ground Testing Simulating GEO Environment

    Publication Year: 2012 , Page(s): 321 - 323
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (638 KB) |  | HTML iconHTML  

    Solar array paddle sizes have been larger to generate power that is enough to operate many devices in only one satellite. The cover glass on solar array paddle can be charged on GEO environment. A flashover discharge is triggered by an electrostatic discharge and propagates at a velocity with discharging the amount of charge stored on the cover glass. Therefore, the charge and current waveform of flashover discharge depend on the paddle size and differential voltage. ESD ground testing needs simulating the flashover current, because the large paddle can cause large flashover. A flashover current simulator has been developed so far in our laboratory. View full abstract»

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IEEE Transactions on Plasma Sciences focuses on plasma science and engineering, including: magnetofluid dynamics and thermionics; plasma dynamics; gaseous electronics and arc technology.

 

 

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