Density and Magnetic Field Asymmetric Kelvin‐Helmholtz Instability

The Kelvin‐Helmholtz (KH) instability can transport mass, momentum, magnetic flux, and energy between the magnetosheath and magnetosphere, which plays an important role in the solar‐wind‐ magnetosphere coupling process for different planets. Meanwhile, strong density and magnetic field asymmetry are often present between the magnetosheath (MSH) and magnetosphere (MSP), which could affect the transport processes driven by the KH instability. Our magnetohydrodynamics simulation shows that the KH growth rate is insensitive to the density ratio between the MSP and the MSH in the compressible regime, which is different than the prediction from linear incompressible theory. When the interplanetary magnetic field (IMF) is parallel to the planet\u27s magnetic field, the nonlinear KH instability can drive a double mid‐latitude reconnection (DMLR) process. The total double reconnected flux depends on the KH wavelength and the strength of the lower magnetic field. When the IMF is anti‐parallel to the planet\u27s magnetic field, the nonlinear interaction between magnetic reconnection and the KH instability leads to fast reconnection (i.e., close to Petschek reconnection even without including kinetic physics). However, the peak value of the reconnection rate still follows the asymmetric reconnection scaling laws. We also demonstrate that the DMLR process driven by the KH instability mixes the plasma from different regions and consequently generates different types of velocity distribution functions. We show that the counter‐streaming beams can be simply generated via the change of the flux tube connection and do not require parallel electric fields

Seven Sisters: a mission to study fundamental plasma physical processes in the solar wind and a pathfinder to advance space weather prediction

This paper summarizes the Seven Sisters solar wind mission concept and the outstanding science questions motivating the mission science objectives. The Seven Sisters mission includes seven individual spacecraft designed to uncover fundamental physical processes in the solar wind and provides up to ≈ 2 days of advanced space weather warnings for 550 Earth days during the mission. The mission will collect critical measurements of the thermal and suprathermal plasma and magnetic fields, utilizing, for the first time, Venus–Sun Lagrange points. The multi-spacecraft configuration makes it possible to distinguish between spatial and temporal changes, define gradients, and quantify cross-scale transport in solar wind structures. Seven Sisters will determine the 3-D structure of the solar wind and its transient phenomena and their evolution in the inner heliosphere. Data from the Seven Sisters mission will allow the identification of physical processes and the quantification of the relative contribution of different mechanisms responsible for suprathermal particle energization in the solar wind

MMS Observations of Energetic Particles in the Magnetosheath: Preliminary Case Studies

Previous studies have shown the formation of large diamagnetic cavities around the Earth’s magnetopause that are filled with highly energetic ions and electrons at 90 degree pitch angles. Statistical study has shown that cavity locations are consistent with expected location of magnetic bottle formation for anti-parallel or component reconnection for given IMF orientation. However, there are few cases that are not consistent with either. In this work we consider the possibility that these particles could originate from foreshock. As a first step we have analyzed MMS magnetosheath crossings to understand the IMF and SW conditions for which we see energetic particles in the magnetosheath

Statistical Study of the Energetic Electron Microinjections at the High-latitude Magnetosphere

Understanding the formation of the seed population for the energetic electrons trapped within the Earth’s Van Allen radiation belts has been under debate for decades. The magnetic reconnection in the Earth’s magnetotail during the substorms is considered to be the main process considered to accelerate the electrons to the tens to hundreds of keV. These electrons are then further injected toward the radiation belts, where they get further accelerated to relativistic energies. Recently, it has been suggested that another source could come from the dayside diamagnetic cavities where electrons and ions can be locally accelerated to hundreds of keV. It has been shown that the acceleration mechanism within cavities can create a strong temperature anisotropy which leads to drift mirror instability and injection of electrons parallel and anti-parallel to magnetic field potentially accessing inner magnetosphere. As a first part of this study, this presentation focuses on the statistical study of the energetic electron microinjections and their relation to solar wind, IMF conditions and local plasma/field parameters. We find total of 165 hours of dispersionless energy-time microinjections in the high latitude pre-dusk sector and they coincidence with the magnetic field variations in the Ultra Low Frequency (ULF) range, often with similar frequencies. Many of these ULF fluctuations show features consistent with mirror mode waves, and can potentially be one of the sources for microinjections due to wave particle interactions

First Observations and Simulations of Multiple Diamagnetic Cavities at Dayside Magnetosphere and their connection to Energetic Electron Microinjections

Despite recent advances in understanding the generation mechanisms of the electron microinjections, it is still unclear how the proposed source origins of the electron microinjections can generate and organize the high-energy electrons as observed in microinjections. Here we present a multisatellite case study of Electron Microinjections observed by the Magnetospheric Multiscale (MMS). During this event, MMS traversed duskward at the Southern hemispheric dayside magnetospheric boundaries, Geotail located at the magnetopause at the dusk equatorial plane observing periodic magnetopause crossings, and THEMIS A and E located at the dawnside magnetosheath encountering several magnetic field depressions characterized by enhanced plasma beta and high fluxes of high-energy electrons. The multipoint spacecraft analysis and high-resolution OpenGGCM magnetohydrodynamic simulations created for real solar wind and IMF orientations during the event show that the two diamagnetic cavities (DMC) had been created by magnetic reconnection at high latitudes in the vicinity of the cusps. MMS detects the microinjections in the vicinity of the southern-hemispheric dusk sector cavity. Simulations also reveal that two additional DMCs are formed at mid-latitudes by remote component reconnection at low latitudes, one of which is observed by THEMIS. We suggest DMCs as a likely source origin of present energetic electron microinjections observed by MMS. The present study provides new insights into the nature and origin of energetic particles within energetic electron microinjections

Asymmetric 3-D Kelvin–Helmholtz instability

It has been demonstrated that the Kelvin–Helmholtz (KH) instability plays an important role in the solar-wind-magnetosphere coupling process for different planets. Driven by a large shear flow, the KH instability can transport the mass, magnetic flux, and energy between the magnetosheath and magnetosphere (or ionosphere). Meanwhile, strong density, temperature, and magnetic field asymmetry often present between the magnetosheath and magnetosphere, which also affects the KH onset condition, and consequently affect the transport processes. It has been shown that the strong plasma beta asymmetry across the current layer will compress the magnetic reconnection rate. Notice that the strong plasma beta asymmetry also indicates a strong asymmetric magnetic field. In this study, we use MHD simulation illustrate that the reconnection rate during the nonlinear interaction between KH instability and reconnection is still higher than the typical magnetic reconnection rate, even with a strong plasma beta asymmetry. However, the variation of reconnection rate as the function of the magnetic asymmetry is still consistent with Cassak-Shay’s scaling. Meanwhile, in the nonlinear stage of the KH instability under Northward IMF condition, a large net mass transport rate occurs only when there is a strong flux content (i.e., ∝ρ/B ) asymmetry via the double-middle-latitude-reconnection (DMLR) process. As such, it is of interest to investigate the influence of the magnetosheath-magnetosphere asymmetry on the nonlinear interaction between the KH instability and magnetic reconnection. This presentation estimates the mass and flux transport rate at different IMF conditions by using MHD with test particle simulations. It also shows how perpendicular to parallel temperature anisotropy will be formed in the 3-D KHI in presence of temperature asymmetry across the magnetopause, due to the change of the magnetic field topology via DMLR. We will also compare the simulation results with recent in-situ spacecraft observations

On the Origin of Energetic Electron Microinjections at High-Latitude Magnetosphere: A Case study using information theory and MMS data

Previous works (e.g., Nykyri+, 2012; Nykyri+2019; Burkholder+2020,2021) have shown that magnetic reconnection can create large-scale diamagnetic cavities in high-latitude magnetosphere where particles can be accelerated to 100s of keV in reconnection quasi-potential. The acceleration mechanism creates strongly perpendicular pitch angle distributions for ions and electrons, likely contributing to the source of the ion temperature anisotropy in high-latitude magnetosphere. Recently, 4 MMS spacecraft flew through dusk-sector southern hemispheric diamagnetic cavity observing strong ULF wave activity, driven by the drift-mirror instability, at the edge of the cavity. The high-energy electrons within these wave field depressions showed counter-streaming pitch angle distributions while ions remained trapped (Nykyri+, 2021, GRL). The Pc5 range ULF waves also contained strong higher frequency plasma wave activity. In this talk we use information theory (mutual information and transfer entropy) and show that energetic electrons during this event indeed originate from diamagnetic cavity and are scattered into the loss cone likely by the oxygen cyclotron waves found inside mirror-mode waves

Analysis of the genetic component of systemic sclerosis in Iranian and Turkish populations through a genome-wide association study

Objectives. SSc is an autoimmune disease characterized by alteration of the immune response, vasculopathy and fibrosis. Most genetic studies on SSc have been performed in European-ancestry populations. The aim of this study was to analyse the genetic component of SSc in Middle Eastern patients from Iran and Turkey through a genome-wide association study.Methods. This study analysed data from a total of 834 patients diagnosed with SSc and 1455 healthy controls from Iran and Turkey. DNA was genotyped using high-throughput genotyping platforms. The data generated were imputed using the Michigan Imputation Server, and the Haplotype Reference Consortium as a reference panel. A meta-analysis combining both case-control sets was conducted by the inverse variance method.Results. The highest peak of association belonged to the HLA region in both the Iranian and Turkish populations. Strong and independent associations between the classical alleles HLA-DRB1*11:04 [P = 2.10 x 10(-24), odds ratio (OR) = 3.14] and DPB1*13:01 (P = 5.37 x 10(-14), OR = 5.75) and SSc were observed in the Iranian population. HLA-DRB1*11:04 (P = 4.90 x 10(-11), OR = 2.93) was the only independent signal associated in the Turkish cohort. An omnibus test yielded HLA-DRB1 58 and HLA-DPB1 76 as relevant amino acid positions for this disease. Concerning the meta-analysis, we also identified two associations close to the genome-wide significance level outside the HLA region, corresponding to IRF5-TNPO3 rs17424921-C (P = 1.34 x 10(-7), OR = 1.68) and NFKB1 rs4648133-C (P = 3.11 x 10(-7), OR = 1.47).Conclusion. We identified significant associations in the HLA region and suggestive associations in IRF5-TNPO3 and NFKB1 loci in Iranian and Turkish patients affected by SSc through a genome-wide association study and an extensive HLA analysis