| 1. |
- Soucek, J., et al.
(författare)
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EMC Aspects Of Turbulence Heating Observer (THOR) Spacecraft
- 2016
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Ingår i: Proceedings Of 2016 Esa Workshop On Aerospace Emc (Aerospace Emc). - : Institute of Electrical and Electronics Engineers (IEEE). - 9789292213039
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Konferensbidrag (refereegranskat)abstract
- Turbulence Heating ObserveR (THOR) is a spacecraft mission dedicated to the study of plasma turbulence in near-Earth space. The mission is currently under study for implementation as a part of ESA Cosmic Vision program. THOR will involve a single spinning spacecraft equipped with state of the art instruments capable of sensitive measurements of electromagnetic fields and plasma particles. The sensitive electric and magnetic field measurements require that the spacecraft-generated emissions are restricted and strictly controlled; therefore a comprehensive EMC program has been put in place already during the study phase. The THOR study team and a dedicated EMC working group are formulating the mission EMC requirements already in the earliest phase of the project to avoid later delays and cost increases related to EMC. This article introduces the THOR mission and reviews the current state of its EMC requirements.
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| 2. |
- Savin, S., et al.
(författare)
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High energy jets in the Earth's magnetosheath : Implications for plasma dynamics and anomalous transport
- 2008
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Ingår i: JETP Letters. - 0021-3640 .- 1090-6487. ; 87:11, s. 593-599
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Tidskriftsartikel (refereegranskat)abstract
- High energy density Jets in the magnetosheath near the Earth magnetopause were observed by Interball-1 [1]. In this paper, we continue the investigation of this important physical phenomenon. New data provided by Cluster show that the magnetosheath kinetic energy density during more than one hour exhibits an average level and a series of peaks far exceeding the kinetic energy density in the undisturbed solar wind. This is a surprising finding because the kinetic energy of the upstream solar wind in equilibrium should be significantly diminished downstream in the magnetosheath due to plasma braking and thermalization at the bow shock. We suggest resolving the energy conservation problem by the fact that the nonequilibrium Jets appear to be locally superimposed on the background equilibrium magnetosheath, and, thus, the energy balance should be settled globally on the spatial scales of the entire dayside magnetosheath. We show that both the Cluster and Interball jets are accompanied by plasma superdiffusion and suggest that they are important for the energy dissipation and plasma transport. The character of the Jet-related turbulence strongly differs From that of known standard cascade models. We infer that these Jets may represent the phenomenon of the general physical occurrence observed in other natural systems, such as heliosphere, astrophysical, and fusion plasmas [2-10].
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| 3. |
- Vaverka, J., et al.
(författare)
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One-Year Analysis of Dust Impact-Like Events Onto the MMS Spacecraft
- 2019
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Ingår i: Journal of Geophysical Research - Space Physics. - : Wiley-Blackwell Publishing Inc.. - 2169-9380 .- 2169-9402. ; 124:11, s. 8179-8190
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Tidskriftsartikel (refereegranskat)abstract
- We present an analysis of 1-year data of dust impacts observed on two of the Earth-orbiting Magnetospheric Multiscale mission (MMS) spacecraft. The dust impact signals were identified in observations of the electric field probes and were registered simultaneously by monopole and dipole configurations of the instrument. This unique setup allows us to reliably identify changes in the spacecraft potential as candidates for dust impacts. We present a detailed study of the properties of the pulses generated by the dust impacts and show the influence of the local plasma environment (spacecraft location in the Earth magnetosphere) on signals generated by dust impacts and their detection. We discuss the credibility of impact identification and possible sources of signal misinterpretation. We find a total of 784 observed events that we can interpret as dust impacts and that we use to derive a dust flux. We show that MMS1 registered 0.7 and MMS3 0.8 dust impact-like events per hour. This corresponds to dust flux of 2.5–6 × 10−5 m−2 s−1.
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| 4. |
- Nemecek, Z., et al.
(författare)
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Secondary Electron Emission And Its Role in the Space Environment
- 2018
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Ingår i: DIVERSE WORLD OF DUSTY PLASMAS. - : AMER INST PHYSICS. - 9780735416178
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Konferensbidrag (refereegranskat)abstract
- The role of dust in the space environment is of increasing interest in recent years and also the fast development of fusion devices with a magnetic confinement brought new issues in the plasma surface interaction. Among other processes, secondary electron emission plays an important role for dust charging in interplanetary space and its importance increases at and above the surfaces of airless bodies like planets, moons, comets or asteroids. A similar situation can be found in many industrial applications where the dust is a final product or an unintentional impurity. The present paper reviews the progress in laboratory investigations of the secondary emission process as well as an evolution of the modeling of the interaction of energetic electrons with dust grains of different materials and sizes. The results of the model are discussed in view of latest laboratory simulations and they are finally applied on the estimation of an interaction of the solar wind and magnetospheric plasmas with the dust attached to or levitating above the lunar surface.
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| 5. |
- Vaverka, Jakub, et al.
(författare)
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Lunar surface and dust grain potentials during the earth's magnetosphere crossing
- 2016
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Ingår i: Astrophysical Journal. - Bristol : Institute of Physics Publishing (IOPP). - 0004-637X .- 1538-4357. ; 825:2
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Tidskriftsartikel (refereegranskat)abstract
- Interaction between the lunar surface and the solar UV radiation and surrounding plasma environment leads to its charging by different processes like photoemission, collection of charged particles, or secondary electron emission (SEE). Whereas the photoemission depends only on the angle between the surface and direction to the Sun and varies only slowly, plasma parameters can change rapidly as the Moon orbits around the Earth. This paper presents numerical simulations of one Moon pass through the magnetospheric tail including the real plasma parameters measured by THEMIS as an input. The calculations are concentrated on different charges of the lunar surface itself and a dust grain lifted above this surface. Our estimations show that (1) the SEE leads to a positive charging of parts of the lunar surface even in the magnetosphere, where a high negative potential is expected; (2) the SEE is generally more important for isolated dust grains than for the lunar surface covered by these grains; and (3) the time constant of charging of dust grains depends on their diameter being of the order of hours for sub-micrometer grains. In view of these results, we discuss the conditions under which and the areas where a levitation of the lifted dust grains could be observed.
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