Background: Recent large studies of third-generation minimally invasive hallux valgus surgery (MIS) have demonstrated significant improvement in clinical and radiologic outcomes. It remains unknown whether these outcomes are maintained the medium to long term. The aim this study was investigate minimum 5-year following MIS hands a high-volume surgeon. Methods: A retrospective observational single highly experienced surgeon case series consecutive patients undergoing primary isolated...

We present an interval of extremely long‐lasting narrow‐band Pc5 pulsations during the recovery phase a large geomagnetic storm. These occurred continuously for many hours and were observed throughout magnetosphere in dusk‐sector ionosphere. The subject this paper is favorable radial alignment Cluster, Polar, geosynchronous satellites dusk sector 3‐hour subset that allows extensive analysis global nature tracing their energy transfer from solar wind to ground. Virtually monochromatic...

Abstract Using the total radiation belt electron content calculated from Van Allen Probe phase space density, time‐dependent and global response of outer during storms is statistically studied. density reduces impacts adiabatic changes in main phase, allowing a separation nonadiabatic effects revealing clear modality repeatable sequence events storm time dynamics. This exhibits an important first invariant ( μ )‐dependent behavior seed (150 MeV/G), relativistic (1,000 ultrarelativistic...

Abstract Southward interplanetary magnetic field (IMF) in the geocentric solar magnetospheric (GSM) reference frame is key element that controls level of space weather disturbance Earth's magnetosphere, ionosphere, and thermosphere. We discuss relation this geoeffective IMF component to ecliptic (GSE) frame, using almost continuous data for 1996–2015 (inclusive), we show large geomagnetic storms are always associated with strong southward, out‐of‐ecliptic GSE frame: Dipole tilt effects,...

Abstract The impact of radial diffusion in storm time radiation belt dynamics is well‐debated. In this study we quantify the changes and variability coefficients during geomagnetic storms. A statistical analysis Van Allen Probes data (2012–2019) conducted to obtain measurements magnetic electric power spectral densities for Ultra Low Frequency (ULF) waves, corresponding coefficients. results show global wave enhancements occur main phase, continue into recovery phase. Local asymmetries...

Background: Patients with severe hallux valgus deformity present technical and operative challenges high rates of recurrence residual deformity. The clinical radiologic outcomes percutaneous surgery for are not known. Methods: A retrospective review consecutive patients a angle (HVA) >40 degrees or intermetatarsal (IMA) >20 who underwent third-generation chevron Akin osteotomy (PECA) correction. Results: Between December 2012 August 2019, 59 feet in 50 PECA. Preoperative follow-up...

Quasilinear theories have been shown to well describe a range of transport phenomena in magnetospheric, space, astrophysical and laboratory plasma “weak turbulence” scenarios. It is known that the resonant diffusion quasilinear theory for case uniform background field may formally particle dynamics when electromagnetic wave amplitude growth rates are sufficiently “small”, bandwidth “large”. However, it important note given spectrum would be expected give rise transport, indeed apply...

Results from 1D Vlasov drift-kinetic plasma simulations reveal how and where auroral electrons are accelerated along Earth's geomagnetic field. In the warm sheet, become trapped in shear Alfvén waves, preventing immediate wave damping. As waves move to regions with larger v(Te)/v(A), their parallel electric field decreases, escape influence. The resulting electron distribution functions compare favorably situ observations, demonstrating for first time a self-consistent link between that form aurora.

Despite the characterization of auroral substorm more than 40 years ago, controversy still surrounds processes triggering onset initiation. That stretching Earth's magnetotail following addition new nightside magnetic flux from dayside reconnection powers is well understood; trigger for explosive energy release at expansion phase not. Using ground‐based data sets with unprecedented combined spatial and temporal coverage, we report discovery localized contemporaneous wave small azimuthal...

In order to make best use of the opportunities provided by space missions such as Radiation Belt Storm Probes, we determine response complementary subionospheric radiowave propagation measurements (VLF), riometer absorption measurements, cosmic noise absorption, and GPS‐produced total electron content (vTEC) different energetic precipitation (EEP). We model relative sensitivity responses these instruments idealized monoenergetic beams precipitating electrons, more realistic EEP spectra...

Abstract We present the first multievent study of spatial and temporal structuring aurora to provide statistical evidence near‐Earth plasma instability which causes substorm onset arc. Using data from ground‐based auroral imagers, we repeatable signatures along‐arc beads, are thought represent ionospheric projection magnetospheric in sheet. show that growth scales these wave‐like fluctuations similar across multiple events, indicating each sudden brightening has a common explanation. find...

Abstract During periods of storm activity and enhanced convection, the plasma density in afternoon sector magnetosphere is highly dynamic due to development plasmaspheric drainage plume (PDP) structure. This significantly affects local Alfvén speed alters propagation ULF waves launched from magnetopause. Therefore, it can be expected that accessibility wave power for radiation belt energization sensitively dependent on recent history magnetospheric convection stage PDP. investigated using a...

The substorm current wedge (SCW) is a fundamental component of geomagnetic substorms. Models tend to describe the SCW as simple line flowing into ionosphere toward dawn and out dusk, linked by westward electrojet. We use multispacecraft observations from perigee passes Cluster 1 4 spacecraft during on 15 January 2010, in conjunction with ground‐based observations, examine spatial structuring temporal variability SCW. At this time, traveled east‐west azimuthally above auroral region. show...

Abstract Typically, ultra‐low frequency (ULF) waves have historically been invoked for radial diffusive transport leading to acceleration and loss of outer radiation belt electrons. At higher frequencies, very low are generally thought provide a mechanism localized through precipitation into the ionosphere In this study we present new electron due direct modulation cone via compressional ULF waves. We case wave activity in tandem with riometer balloon‐borne across keV‐MeV energies...

Abstract Energy conversion on the dipolarization fronts (DFs) has attracted much research attention through suggestion that intense current densities associated with DFs can modify more global magnetotail system. The structures a DF are at scale of one to few ion gyroradii, and their duration is comparable spacecraft's spin period. Hence, it crucial understand physical mechanisms measurements timescale shorter than We present case study whereby we use from Magnetospheric Multiscale (MMS)...

Substorms are fundamental and dynamic processes in the magnetosphere, converting captured solar wind magnetic energy into plasma energy. These substorms have been suggested to be a key driver of energetic electron enhancements outer radiation belts. inject keV "seed" population inner magnetosphere which is subsequently energized through wave-particle interactions up relativistic energies; however, extent enhance belts, either directly or indirectly, has never before quantified. In this...

Abstract Radiation belt codes evolve electron dynamics due to resonant wave‐particle interactions. It is not known how best incorporate in the case of a wave power spectrum that varies considerably on “sub‐grid” timescale shorter than computational time‐step radiation model Δ t RBM , particularly if amplitude reaches high values. Timescales associated with growth rate thermal instabilities are very short, and typically much . We use kinetic code study interactions whistler‐mode waves...

In this paper, we present case studies of the optical and magnetic signatures characteristics first minute substorm expansion phase onset observed in ionosphere. We find that for two isolated substorms, pulsations 24–96 s period wavelet band are colocated time space with formation development small‐scale undulations along most equatorward preexisting auroral arc prior to breakup. These undergo an inverse spatial cascade into vortices release westward traveling surge. also a study multiple...

We present a detailed case study of the characteristics auroral forms that constitute first ionospheric signatures substorm expansion phase onset. Analysis optical frequency and along‐arc (azimuthal) wave number spectra provides strongest constraint to date on potential mechanisms instabilities in near‐Earth magnetosphere accompany onset which precede poleward arc breakup. evaluate growth rates as function azimuthal determine whether these are consistent with current models mechanism. find...

Abstract Different terrestrial space weather indicators (such as geomagnetic indices, transpolar voltage, and ring current particle content) depend on different coupling functions (combinations of near‐Earth solar wind parameters), previous studies also reported a dependence the averaging timescale, τ . We study relationships am SME indices to power input into magnetosphere P α , estimated using optimum exponent for range between 1 min year. The effect missing data is investigated by...

Abstract Cold plasma theory and parallel wave propagation are often assumed when approximating the whistler mode magnetic field power from electric observations. The current study is first to include normal angle Electric Magnetic Field Instrument Suite Integrated Science package on board Van Allen Probes in conversion factor, thus allowing for accuracy of these assumptions be quantified. Results indicate that removing assumption does not significantly affect calculated plasmaspheric hiss...

Abstract The onset of an auroral substorm is generally thought to occur on a quiet, homogeneous arc. We present statistical study independently selected arcs and find that over 90% the studied have resolvable characteristic spatial scales in form beads. vast majority (~88%) beads small amplitudes relative background, making them invisible without quantitative analysis. This confirms are highly likely be ubiquitous all arcs, rather than special case phenomena as previously thought. Moreover,...

Abstract Ultralow frequency (ULF) waves in the magnetosphere are involved energization and transport of radiation belt particles strongly driven by external solar wind. However, interdependency wind parameters variety wind‐magnetosphere coupling processes make it difficult to distinguish effect individual predict magnetospheric wave power using properties. We examine 15 years dayside ground‐based measurements at a single representative (2.5 mHz) magnetic latitude (corresponding L ∼ 6.6 R E...

Using the reconstruction of power input to magnetosphere given in Paper 1 (arXiv:1708.04904), we reconstruct annual means geomagnetic indices over past 400 years within a 1-sigma error +/-20 pc. In addition, study behaviour lognormal distribution daily and hourly values about these show that can also fraction geomagnetically-active (storm-like) days (substorm-like) hours each year accuracies 50-60 The results are first physics-based quantification space weather conditions both Dalton Maunder...

Abstract Wave‐particle interactions play a crucial role in energetic particle dynamics the Earth's radiation belts. However, relative importance of different wave modes these is poorly understood. Typically, this assessed during geomagnetic storms using statistically averaged empirical models as function activity advanced belt simulations. statistical averages characterize extreme events such that storm‐time ultralow frequency power typically larger than derived over solar cycle and Kp poor...