Early Observations from the Solar Orbiter SWA/Electron Analyser System

2021 ◽  
Author(s):  
Christopher Owen ◽  
Keyword(s):  
Solar Wind ◽  
Field Vector ◽  
Field Of View ◽  
High Time Resolution ◽  
Angle Distribution ◽  
Pitch Angle Distribution ◽  
Burst Mode ◽  
Steering Mechanism ◽  
Operational Issues ◽  
Electrostatic Analyser

<p>Solar Orbiter carries a total of 10 instrument suites making up the payload for the mission.  One of these, the Solar Wind Analyser (SWA) instrument, is comprised of 3 sensor units which are together served by a central DPU unit.  Of particular focus in this presentation are the early measurements from one of these sensors, the Electron Analyser System (EAS).  EAS is a dual-head, top-hat electrostatic analyser system that is capable of making 3D measurements of solar wind electrons at energies below ~5 keV from a vantage point at the end of a 4-metre boom extending into the shadow of the spacecraft.  The sensor was accommodated in this location to both maximise the unobstructed field of view and to minimise the effect of spacecraft related disturbances on the low-energy (less than a few tens of eV) electrons expected the core population of the solar wind.</p><p>To date the SWA instrument sensors have operated sporadically during the mission cruise phase, which began in June 2020.  This is due to a number of operational issues faced by the SWA team, which mean we have not been able to take data in a continuous manner.  However, the data that has been taken shows the clear promise of the SWA measurements, in general, once these issues can be overcome.  For example, EAS is using a novel sample steering mechanism in burst mode which, with reference to a magnetic field vector shared onboard by the MAG instrument, allows the capture of the electron pitch angle distribution at unusually high time resolution.  We discuss these observations here, and illustrate the potential science returns from the burst mode.  We also present results from the new EAS observations in the vicinity of reconnecting current sheets in the solar wind, to more generally illustrate the capability of the sensor. </p>

Ultra-relativistic electron’s pitch angle distribution narrowing associated with the solar wind density enhancement

2020 ◽  
Author(s):  
Lun Xie ◽  
Ying Xiong ◽  
Suiyan Fu ◽  
Zuyin Pu
Keyword(s):  
Solar Wind ◽  
Plasma Sheet ◽  
Pitch Angle ◽  
Dense Plasma ◽  
Particle Interaction ◽  
Angle Distribution ◽  
Pitch Angle Distribution ◽  
Solar Wind Density ◽  
Wave Particle Interaction ◽  
Emic Waves

<p>Electron pitch angle distribution (PAD) is a critical parameter in the study of the dynamics of the radiation belt electrons. It is well known that solar wind pressure has an impact on the PAD of the geomagnetically trapped electrons. Using the Van Allen Probes' data, we find that the MeV electron PAD at 4.5<L*<5.5 became narrowing (PAD is mainly concentrated at 90 degree) for over three days during a prolonged enhancement of the solar wind number density on November 27-30, 2015. During that period, the EMIC waves are observed by Van Allen Probe-A and ground stations on the afternoon and dusk MLTs at L>4. Meanwile, the precipitations of tens of keV protons and MeV electrons are observed by POES satellites. Additionally, there is a growing dip in electron phase space density at L*~5, indicating a local loss caused by the wave-particle interaction. The narrowing of the electron PAD is energy-dependent and the PAD is more anisotropic for electrons with higher energy, which is consistent with the wave-particle interaction with the EMIC waves. Furthermore, previous studies have shown that high solar wind density can lead to a hot and dense plasma sheet. The inward penetration of a dense plasma-sheet down to 4 Re has been confirmed by THEMIS spacecraft. We suggest that the overlap of the plasma sheet and the plasmasphere provide a favorable condition for exciting EMIC waves and the loss of small pitch angle electrons by EMIC waves can lead to the electron PAD narrowing. </p><div> </div>

Design of Interplanetary Observation Terminal based on All Programmable System-on-Chip

2021 ◽  
Author(s):  
Haonan Jin ◽  
Lesheng He ◽  
Liang Dong ◽  
Yongliang Tan ◽  
Qingyang Kong
Keyword(s):  
Solar Wind ◽  
Human Life ◽  
Average Power ◽  
Experimental Tests ◽  
System On Chip ◽  
High Time Resolution ◽  
Processing Scheme ◽  
Gigabit Ethernet ◽  
System Memory ◽  
On Chip

The drastic changes in the solar wind will cause serious harm to human life. Monitoring interplanetary scintillation (IPS) can predict solar wind activity, thereby effectively reducing the harm caused by space weather. Aiming at the problem of the lack of the ability to observe IPS phenomenon of the 40-meter radio telescope at the Yunnan Astronomical Observatory of China in the frequency band around 300MHz, an IPS real-time acquisition and processing scheme based on all programmable system-on-chip(APSoC) was proposed. The system calculates the average power of 10ms IPS signal in PL-side and transmits it to the system memory through AXI4 bus. PS-side reads the data, takes logarithms, packages it, and finally transmits it to the LabVIEW host computer through gigabit Ethernet UDP mode for display and storage. Experimental tests show that the system functions correctly, and the PL-side power consumption is only 1.955 W, with a high time resolution of 10ms, and no data is lost in 24 hours of continuous observation, with good stability. The system has certain application value in IPS observation.

Influence of time-variable solar wind on the response of Mercury’s magnetosphere

2021 ◽  
Author(s):  
Sae Aizawa ◽  
Nicolas André ◽  
Ronan Modolo ◽  
Elisabeth Werner ◽  
Jim Slavin ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Charged Particles ◽  
Time Variable ◽  
Low Energy ◽  
Field Of View ◽  
Plasma Measurement ◽  
Electrons And Ions ◽  
Low Energy Electrons ◽  
The Magnetic Field

<p><span lang="EN-GB">BepiColombo is going to conduct its first Mercury flyby in October 2021. During this flyby,  plasma measurement will be obtained and bring new insights on the Hermean magnetosphere and its interaction with the Sun despite the limited field of view of the instruments during the cruise phase. Unlike Mariner-10 ion measurements will be obtained, and unlike MESSENGER, low energy electrons and ions will be measured simultaneously. In this study, we have revisited Mariner 10 and MESSENGER observations with the help of the global hybrid model LatHyS in order to understand the influence of time-variable solar wind and to constraint the plasma environment. We are able to reproduce the magnetic field observations of Mariner 10 along its trajectory with in particular two distinct signatures consisting of a quiet and disturbed state of the magnetosphere. In addition, the plasma spectrogram is also collected in the model and this enables us to detail the properties of the charged particles observed during the flyby. We will discuss all these signatures both in term of an interaction with a time-variable solar wind and localized processes occurring in the magnetosphere. We will then present the virtual sampling of both the magnetic field and plasma spectrogram along BepiColombo’s first Mercury flyby trajectory and discuss the possible signatures to be observed at that time.</span></p>

scholarly journals On the probability distribution function of small-scale interplanetary magnetic field fluctuations

2004 ◽  
Vol 22 (10) ◽  
pp. 3751-3769 ◽  
Author(s):  
R. Bruno ◽  
V. Carbone ◽  
L. Primavera ◽  
F. Malara ◽  
L. Sorriso-Valvo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Robust Statistics ◽  
Interplanetary Space ◽  
Parametric Instability ◽  
Field Vector ◽  
Small Scale ◽  
Magnetic Fluctuations ◽  
Mhd Turbulence ◽  
The One

Abstract. In spite of a large number of papers dedicated to the study of MHD turbulence in the solar wind there are still some simple questions which have never been sufficiently addressed, such as: a) Do we really know how the magnetic field vector orientation fluctuates in space? b) What are the statistics followed by the orientation of the vector itself? c) Do the statistics change as the wind expands into the interplanetary space? A better understanding of these points can help us to better characterize the nature of interplanetary fluctuations and can provide useful hints to investigators who try to numerically simulate MHD turbulence. This work follows a recent paper presented by some of the authors which shows that these fluctuations might resemble a sort of random walk governed by Truncated Lévy Flight statistics. However, the limited statistics used in that paper did not allow for final conclusions but only speculative hypotheses. In this work we aim to address the same problem using more robust statistics which, on the one hand, forces us not to consider velocity fluctuations but, on the other hand, allows us to establish the nature of the governing statistics of magnetic fluctuations with more confidence. In addition, we show how features similar to those found in the present statistical analysis for the fast speed streams of solar wind are qualitatively recovered in numerical simulations of the parametric instability. This might offer an alternative viewpoint for interpreting the questions raised above.

scholarly journals Comparison between CNA and energetic electron precipitation: simultaneous observation by Poker Flat Imaging Riometer and NOAA satellite

2005 ◽  
Vol 23 (5) ◽  
pp. 1555-1563 ◽  
Author(s):  
Y.-M. Tanaka ◽  
M. Ishii ◽  
Y. Murayama ◽  
M. Kubota ◽  
H. Mori ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Electron Flux ◽  
Energetic Electron ◽  
Energetic Particles ◽  
Electron Precipitation ◽  
Angle Distribution ◽  
Pitch Angle Distribution ◽  
Loss Cone ◽  
Isotropic Pitch ◽  
Trapped Electron

Abstract. The cosmic noise absorption (CNA) is compared with the precipitating electron flux for 19 events observed in the morning sector, using the high-resolution data obtained during the conjugate observations with the imaging riometer at Poker Flat Research Range (PFRR; 65.11° N, 147.42° W), Alaska, and the low-altitude satellite, NOAA 12. We estimate the CNA, using the precipitating electron flux measured by NOAA 12, based on a theoretical model assuming an isotropic pitch angle distribution, and quantitatively compare them with the observed CNA. Focusing on the eight events with a range of variation larger than 0.4dB, three events show high correlation between the observed and estimated CNA (correlation coefficient (r0)>0.7) and five events show low correlation (r0<0.5). The estimated CNA is often smaller than the observed CNA (72% of all data for 19 events), which appears to be the main reason for the low-correlation events. We examine the assumption of isotropic pitch angle distribution by using the trapped electron flux measured at 80° zenith angle. It is shown that the CNA estimated from the trapped electron flux, assuming an isotropic pitch angle distribution, is highly correlated with the observed CNA and is often overestimated (87% of all data). The underestimate (overestimate) of CNA derived from the precipitating (trapped) electron flux can be interpreted in terms of the anisotropic pitch angle distribution similar to the loss cone distribution. These results indicate that the CNA observed with the riometer may be quantitatively explained with a model based on energetic electron precipitation, provided that the pitch angle distribution and the loss cone angle of the electrons are taken into account. Keywords. Energetic particles, precipitating – Energetic particles, trapped – Ionosphere-magnetosphere interactions

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