First-year ion-acoustic wave observations in the solar wind by the RPW/TDS instrument on board Solar Orbiter

Context. Electric field measurements of the Time Domain Sampler (TDS) receiver, part of the Radio and Plasma Waves (RPW) instrument on board Solar Orbiter, often exhibit very intense broadband wave emissions at frequencies below 20 kHz in the spacecraft frame. During the first year of the mission, the RPW/TDS instrument was operating from the first perihelion in mid-June 2020 and through the first flyby of Venus in late December 2020. Aims. In this paper, we present a year-long study of electrostatic fluctuations observed in the solar wind at an interval of heliocentric distances from 0.5 to 1 AU. The RPW/TDS observations provide a nearly continuous data set for a statistical study of intense waves below the local plasma frequency. Methods. The on-board and continuously collected and processed properties of waveform snapshots allow for the mapping plasma waves at frequencies between 200 Hz and 20 kHz. We used the triggered waveform snapshots and a Doppler-shifted solution of the dispersion relation for wave mode identification in order to carry out a detailed spectral and polarization analysis. Results. Electrostatic ion-acoustic waves are the most common wave emissions observed between the local electron and proton plasma frequency by the TDS receiver during the first year of the mission. The occurrence rate of ion-acoustic waves peaks around perihelion at distances of 0.5 AU and decreases with increasing distances, with only a few waves detected per day at 0.9 AU. Waves are more likely to be observed when the local proton moments and magnetic field are highly variable. A more detailed analysis of more than 10000 triggered waveform snapshots shows the mean wave frequency at about 3 kHz and wave amplitude about 2.5 mV/m. The wave amplitude varies as R−1.38 with the heliocentric distance. The relative phase distribution between two components of the E-field projected in the Y-Z Spacecraft Reference Frame (SRF) plane shows a mostly linear wave polarization. Electric field fluctuations are closely aligned with the directions of the ambient field lines. Only a small number (3%) of ion-acoustic waves are observed at larger magnetic discontinuities

SdiA, an N-Acylhomoserine Lactone Receptor, Becomes Active during the Transit of Salmonella enterica through the Gastrointestinal Tract of Turtles

encode a LuxR-type AHL receptor, SdiA, they cannot synthesize AHLs. In vitro, it is known that SdiA can detect AHLs produced by other bacterial species..We conclude that the normal gastrointestinal microbiota of most animal species do not produce AHLs of the correct type, in an appropriate location, or in sufficient quantities to activate SdiA. However, the results obtained with turtles represent the first demonstration of SdiA activity in animals

Ray tracing study of propagation of lower-band whistler-mode emissions in outer radiation belts: A statistical approach

International audienceLower-band whistler-mode electromagnetic waves play an important role in the dynamics of outer radiation belts. To improve our understanding of ocurrence and behavior of these emissions, we run series of ray tracing simula- tions in non-relativistic hot plasma for a broad range of initial conditions, analyse the spatial dependence of wave properties and compare our results with long-term experimental data from the Cluster mission. The focus of the study is on the wave vector angle and wave intensity distribution of chorus emissions at higher latitudes. In this region, realistic empirical models of electron density distribution and Earths magnetic field are employed to obtain reliable data from the simulation. Damping and growth of waves is computed during the propagation, based on an empirical model of electron flux in outer magnetosphere. Other wave properties of importance are ellipticity of polarization and Poynting vector angle, analysed here in dependence on latitude and magnetic field line

Poynting flux analysis of whistler-mode chorus using THEMIS data

International audienceWe present a statistical analysis of Poynting fluxes for magnetospheric whistler-mode chorus emission observed on THEMIS (Time History of Events and Macroscale Interactions during Substorms). Results are shown for chorus rising and falling tones. The aim of this study is to clearly distinguish between chorus from equatorial source regions and from sources at higher magnetic latitudes, i.e., from dayside pockets of minimum magnetic field. Furthermore, the topic of magnetospherically reflected chorus as a possible process to produce falling tones will be discussed

An Experiment to Prove the Effect of Low-Level Magnetic Fields Resulting from Ionospheric Changes on Humans

The investigation presented in the paper was performed in the laboratories of the Department of Theoretical and Experimental Electrical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, between April 22 and June 26, 2014. We examined a homogeneous sample of male and female participants comprising a total of 49 persons aged 19 to 26. The time required for the measurement of psychophysiological parameters corresponded to 19 minutes, encompassing five stages: Basic (5 mins.), Color (2 mins.), Rest (5 mins.), Math (2 mins.), and Rest (5 mins.). All the measuring cycles were carried out using a BioGraph Infiniti device (Thought Technology, Ltd.). Generally, the impact of the environment upon living organisms constitutes a crucial problem examined by today’s science. In this context, the present article describes the results of an investigation focused on ionosphere parameter variation and its role in the basic function of the nervous system. The discussed research concentrates on the measurement and detection of changes in the region of very low electromagnetic field frequencies; the authors introduce and verify related theoretical and experimental procedures to define the effects that influence brain activity and the cardiovascular system

The rise of AGILE demand response: enabler and foundation for change

The distributed resources – distributed generations, storage, electric vehicles and smart appliances – have fueled many disruptions in the conventional grid dynamics. Increasing tough and competitive situations at demand-side have led the stakeholders of power system to reform, because people are more informed and can make decisions that has given rise to turbulent and volatile electricity markets. In such highly diversified and open market environment, the integrated control strategy has expedited the concept of Demand Response. Currently, the important questions in the area of demand response are likely to shift from whether to adopt dynamic pricing to how to achieve fast demand response by the combination of technology and a competitive retail electricity market. This paper assembles the part and parcel in the light of existing technologies for the development of the concept of agility in demand response, that can play a role as a service package which is designed to meet the customer satisfaction efficiently and reliably as well as improve the market responsiveness. For the first time, this paper encompasses the concept of Agile Demand Response that is defined as the ability of power system to survive and prosper in the competitive retail market by reacting to the market needs fast and effectively which are driven by the customers. This paper also presents the key enablers of the agile demand response, which are (1) Retail Market, (2) Virtual Supply-demand matching mechanism, (3) Integrated information system and (4) Stay Committed. The paper concludes that by bringing the enablers together – Agile DR improves the responsiveness to the retail market changes unambiguously