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The Earth’s magnetosphere and its bow shock, which is formed by the interaction of the supersonic solar wind with the terrestrial magnetic field, constitute a rich natural laboratory enabling in situ investigations of universal plasma processes. Under suitable interplanetary magnetic field conditions, a foreshock with intense wave activity forms upstream of the bow shock. So-called 30 s waves, named after their typical period at Earth, are the dominant wave mode in the foreshock and play an important role in modulating the shape of the shock front and affect particle reflection at the shock. These waves are also observed inside the magnetosphere and down to the Earth’s surface, but how they are transmitted through the bow shock remains unknown. By combining state-of-the-art global numerical simulations and spacecraft observations, we demonstrate that the interaction of foreshock waves with the shock generates earthward-propagating, fast-mode waves, which reach the magnetosphere. These findings give crucial insight into the interaction of waves with collisionless shocks in general and their impact on the downstream medium.

Interplanetary (IP) shocks are driven in the heliosphere by fast coronal ejecta, they can accelerate particles and are associated with solar energetic particle and energetic storm particle events. IP shocks can interact with structures in the solar wind and with magnetospheres. We show how the properties of an IP shock change when it interacts with a small‐scale flux rope‐like structure (FRLS). Data from Cluster, Wind, and ACE show that the spacecraft observed the shock‐FRLS interaction at different stages of evolution. Wind and ACE observed the FRLS at shock crossing; Cluster observed the FRLS downstream, after it had crossed the shock. The shock‐FRLS interaction changes shock geometry, affecting ion injection processes, energetic particles fluxes, and the upstream/downstream regions. While Wind and ACE observed a quasi‐perpendicular shock, Cluster crossed a quasi‐parallel shock and a foreshock with a variety of ion distributions. The FRLS modified the shock on scales of at least ∼ 10–20 RE. The complexity of the ion foreshock measured by Cluster is explained by the dynamics of the shock transitioning from quasi‐perpendicular to quasi‐parallel and the geometry of the magnetic field within the flux rope. Fluxes of particles with energy up to 125 keV are affected by the FRLS‐shock interaction, modulating the associated energetic storm particle event. The interaction of a FRLS with an IP shock has not been discussed before using multispacecraft observations. Interactions like this should occur often along the shock fronts; hence, they are important for a better understanding of shock structure, evolution, and particle acceleration. Shock interaction with small flux ropes in the solar wind can change shock geometry and impact ion injection at the shockInterplanetary shock interaction with flux ropes can modify the upstream and downstream regionsFluxes of particles with energy up to 125 keV are affected by the FRLS‐shock interaction, modulating associated ESP events

Nanofiber-based drug-delivery systems are widely applicable for specific drug release, according to the target location and timing, to achieve the desired therapeutic effects. A nanofiber formulation is usually developed for a specific drug, and a change of drug can drastically affect the release kinetics from the same delivery system. Here, we review the various types of nanofibers from the latest available literature, based on their composition and drug-release properties. Nanofibers are characterized according to their mode of drug release, and according to their structure and composition. Nanofibers designed for immediate drug release have generally simple structures. A suitable polymer, large surface-to-volume ratio, and high porosity of the nanofiber mesh are exploited to achieve immediate drug release. Nanofibers for modified drug release are classified here according to their drug-release characteristics, as prolonged, stimulus-activated, and biphasic. In general, swellable or degradable polymers are used to modify the drug release. As well as the selection of the polymer, the process and environmental conditions can significantly influence the release properties of nanofibers. The formulation of nanofibers is very complex and depends on many variables, although at the same time, the design of the formulation offers many opportunities to achieve the desired nanofiber drug-release properties.

We use the multispacecraft capabilities of the Cluster and Time History of Events and Macroscale Interactions during Substorms (THEMIS) missions to show that two types of foreshock may be detected in spacecraft data. One is the global foreshock that appears upstream of the Earth's quasi‐parallel bow shock under steady or variable interplanetary magnetic field. Another type is a traveling foreshock that is bounded by two rotational discontinuities in the interplanetary magnetic field and propagates along the bow shock. Foreshock compressional boundaries are found at the edges of both types of foreshock. We show that isolated foreshock cavities are a subset of the traveling foreshocks that form when two bounding rotational discontinuities are so close that the ultralow‐frequency waves do not develop in the region between them. We also report observations of a spontaneous hot flow anomaly inside a traveling foreshock. This means that other phenomena, such as foreshock cavitons, may also exist inside this type of foreshock. In the second part of this work we present statistical properties of phenomena related to the foreshock, namely, foreshock cavities, cavitons, spontaneous hot flow anomalies, and foreshock compressional boundaries. We show that spontaneous hot flow anomalies are the most depleted transient structures in terms of the Bfield and plasma density inside them and that the foreshock compressional boundaries and foreshock cavities are closely related structures. Solar wind (SW) is ionized and magnetized gas propagating radially away from the Sun at supersonic speeds. When it encounters obstacles, such as our planet's magnetosphere, the SW is decelerated, deflected, and heated in a thin shock wave that stands in front of the obstacle. In case of Earth, its shock wave is supercritical, meaning that it reflects a portion of incoming SW particles (ions and electrons) that are reflected back sunward. If the conditions are right, these particles escape far upstream. The interaction of these reflected particles with the SW ones creates a region upstream of the Earth's bow shock called the foreshock region. In it the magnetic field is perturbed and different populations of ions inhabit it. Such region is called global foreshock of Earth. Here we describe another type of foreshock, which we call traveling foreshock, that occurs when the upstream interplanetary magnetic field (IMF) changes its orientation. This occurs since the IMF is composed of magnetic flux tubes that are not straight and are convected by the SW antisunward. In order to distinguish between the global and traveling foreshocks, multispacecraft observations are required. We discuss the relationships of different types of foreshocks with different foreshock phenomena. Different types of foreshocks existRelations between different types of foreshocks and foreshock transient phenomenaAll foreshock phenomena are put in a single scheme in solar foreshock coordinates

We discuss observations of the journey throughout the Solar System of a large interplanetary coronal mass ejection (ICME) that was ejected at the Sun on 14 October 2014. The ICME hit Mars on 17 October, as observed by the Mars Express, Mars Atmosphere and Volatile EvolutioN Mission (MAVEN), Mars Odyssey, and Mars Science Laboratory (MSL) missions, 44 h before the encounter of the planet with the Siding‐Spring comet, for which the space weather context is provided. It reached comet 67P/Churyumov‐Gerasimenko, which was perfectly aligned with the Sun and Mars at 3.1 AU, as observed by Rosetta on 22 October. The ICME was also detected by STEREO‐A on 16 October at 1 AU, and by Cassini in the solar wind around Saturn on the 12 November at 9.9 AU. Fortuitously, the New Horizons spacecraft was also aligned with the direction of the ICME at 31.6 AU. We investigate whether this ICME has a nonambiguous signature at New Horizons. A potential detection of this ICME by Voyager 2 at 110–111 AU is also discussed. The multispacecraft observations allow the derivation of certain properties of the ICME, such as its large angular extension of at least 116°, its speed as a function of distance, and its magnetic field structure at four locations from 1 to 10 AU. Observations of the speed data allow two different solar wind propagation models to be validated. Finally, we compare the Forbush decreases (transient decreases followed by gradual recoveries in the galactic cosmic ray intensity) due to the passage of this ICME at Mars, comet 67P, and Saturn. Study of the propagation of an ICME up to 111 AU; comparison of Forbush decreases triggered by the same ICME at 1.4, 3.1, and 9.9 AUModel‐predicted ICME arrival times are in agreement with the observationsAn ICME disturbed the Solar wind during the Siding Spring comet flyby at Mars on 19 October 2014

This paper is a phenomenological description of the ionospheric plasma and induced magnetospheric boundary (IMB) response to two different types of upstream solar wind events impacting Mars in March 2008, at the solar minimum. A total of 16 Mars Express orbits corresponding to five consecutive days is evaluated. Solar TErrestrial RElations Observatory‐B (STEREO‐B) at 1 AU and Mars Express and Mars Odyssey at 1.644 AU detected the arrival of a small transient interplanetary coronal mass ejection (ICME‐like) on the 6 and 7 of March, respectively. This is the first time that this kind of small solar structure is reported at Mars's distance. In both cases, it was followed by a large increase in solar wind velocity that lasted for ~10 days. This scenario is simulated with the Wang‐Sheeley‐Arge (WSA) ‐ ENLIL + Cone solar solar wind model. At Mars, the ICME‐like event caused a strong compression of the magnetosheath and ionosphere, and the recovery lasted for ~3 orbits (~20 h). After that, the fast stream affected the upper ionosphere and the IMB, which radial and tangential motions in regions close to the subsolar point are analyzed. Moreover, a compression in the Martian plasma system is also observed, although weaker than after the ICME‐like impact, and several magnetosheath plasma blobs in the upper ionosphere are detected by Mars Express. We conclude that, during solar minimum and at aphelion, small solar wind structures can create larger perturbations than previously expected in the Martian system. Martian plasma system response to space weather disturbances during low solar activityPropagation of an ICME‐like transient and a fast solar wind stream from STEREO‐B to MarsLongitudinal and radial inner boundary movements at Mars

Magnetosheath jets are localized plasma structures with high dynamic pressure which are frequently observed downstream of the Earth's bow shock. In this work we analyze Magnetospheric MultiScale magnetic field and plasma data and show that jets can be found in the quasi‐perpendicular magnetosheath in regions permeated by Mirror mode waves (MMWs). We show that structures identified as jets by their enhanced dynamic pressure can have very different internal structure, with variable signatures in magnetic field magnitude and components, velocity, and density and can be associated to ion distribution functions of various types. This suggests that jets observed in the quasi‐perpendicular magnetosheath are generated by different mechanisms. We find that jets can be related to traveling foreshocks, flux transfer events, and some have MMWs inside them. Our results suggest that some jets have a local source and their formation does not depend on upstream structures. We find that different types of ion distributions can exist inside the jets, while in some cases anisotropic distributions are present, in others counterstreaming distributions exist. We also show that for jets with MMWs inside them, ion distributions can be modulated. This highlights the importance of using ion distributions to identify and classify different types of jets. We study high speed magnetosheath jets coexisting with mirror mode wavesWe use Magnetospheric MultiScale data to show that high speed magnetosheath jets have a much more complex structure than previously thought. Velocity distribution functions can be a tool to describe the micro‐physics inside jetsHigh speed jets in the quasi‐perpendicular magnetosheath could have different generation mechanisms that those in the quasi‐parallel sheath We study high speed magnetosheath jets coexisting with mirror mode waves We use Magnetospheric MultiScale data to show that high speed magnetosheath jets have a much more complex structure than previously thought. Velocity distribution functions can be a tool to describe the micro‐physics inside jets High speed jets in the quasi‐perpendicular magnetosheath could have different generation mechanisms that those in the quasi‐parallel sheath

We study the interaction of upstream ultralow frequency (ULF) waves with collisionless shocks by analyzing the outputs of 11 2D local hybrid simulation runs. Our simulated shocks have Alfvénic Mach numbers between 4.29 and 7.42 and their θBNangles are 15°, 30°, 45°, and 50°. The ULF wave foreshocks develop upstream of all of them. The wavelength and the amplitude of the upstream waves exhibit a complex dependence on the shock's MAand θBN. The wavelength positively correlates with both parameters, with the dependence on θBNbeing much stronger. The amplitude of the ULF waves is proportional to the product of the reflected beam velocity and density, which also depend on MAand θBN. The interaction of the ULF waves with the shock causes large‐scale (several tens of upstream ion inertial lengths) shock rippling. The properties of the shock ripples are related to the ULF wave properties, namely their wavelength and amplitude. In turn, the ripples have a large impact on the ULF wave transmission across the shock because they change local shock properties (θBN, strength), so that different sections of the same ULF wavefront encounter shock with different characteristics. Downstream fluctuations do not resemble the upstream waves in terms the wavefront extension, orientation or their wavelength. However, some features are conserved in the Fourier spectra of downstream compressive waves that present a bump or flattening at wavelengths approximately corresponding to those of the upstream ULF waves. In the transverse downstream spectra, these features are weaker. We address the problem of what happens to upstream ultralow frequency (ULF) waves as they reach shocks and are carried into the downstream region. We do this by analyzing the results of 11 2.5D local hybrid simulations of collisionless shocks. We find that the waves are not simply transmitted into the downstream region but that their identity is largely destroyed, as the downstream fluctuations do not resemble the upstream waves neither in wavelengths nor in appearance. However, some features observed in the Fourier spectra of upstream ULF waves are conserved in the Fourier spectra of compressive downstream fluctuations. Upstream ultralow frequency (ULF) waves are not simply transmitted across collisionless shocksSome spectral features of compressive upstream ULF waves are conserved in the spectra of downstream fluctuationsThere is some correlation between the properties of the shock ripples and the foreshock ULF waves Upstream ultralow frequency (ULF) waves are not simply transmitted across collisionless shocks Some spectral features of compressive upstream ULF waves are conserved in the spectra of downstream fluctuations There is some correlation between the properties of the shock ripples and the foreshock ULF waves

We study the interaction of three solar wind (SW) structures, two stream interaction regions, and one interplanetary coronal mass ejection, with Mars’ plasma environment during November 20–27, 2007. This period corresponds to the solar minimum between the solar cycles 23 and 24 which was characterized by very low values of the SW density and dynamic pressure and low interplanetary magnetic field magnitude. During that time the Mars Express orbit was in the terminator plane, while the Earth, Sun, and Mars were almost aligned, so we use the Advance Composition Explorer and Solar Terrestrial Relations Observatory probes as SW monitors in order to identify and characterize the structures that later hit Mars. We find that the passage of these structures caused strong variations in the bow shock location (between 2.2 and 3.0 RM), compression of the magnetospheric cavity (up to 45%), and an increased transterminator flow below 2 RM(by a factor of ≤ 8). This study shows that during times of low solar activity, modest space weather phenomena may cause large variations of plasma flow at Mars. Unlike Earth, Mars does not possess a global magnetic field. Instead it is its ionosphere that represents the obstacle for the solar wind (SW) and thus the induced magnetosphere, magnetosheath, and the bow shock are formed. We make use of the fact that in November 2007, so during the solar minimum 23/24, Mars Express orbit laid in a terminator plane, which made it possible to study transterminator planetary plasma flow. During November 20–27, 2007 Mars interacted with two stream interaction regions and one interplanetary coronal mass ejection. All of these phenomena were of moderate intensity. We know this since at the time Mars and Earth were aligned, so we are able to use Advance Composition Explorer, Solar Terrestrial Relations Observatory (STEREO A), and STEREO B spacecraft as solar monitors. We show that during solar minima moderate SW structures may cause large planetary transterminator flows. These also show variations of their chemistry compositions. Interaction of Mars’ plasma environment with the solar wind (SW) structures during solar minimum 23/24Moderate SW structures interacting with Mars may cause enhanced transterminator planetary ion flowsDuring such perturbed times the planetary ion transterminator flow exhibits strong variations of relative ion abundances Interaction of Mars’ plasma environment with the solar wind (SW) structures during solar minimum 23/24 Moderate SW structures interacting with Mars may cause enhanced transterminator planetary ion flows During such perturbed times the planetary ion transterminator flow exhibits strong variations of relative ion abundances

In the Earth's magnetosheath plasma waves, nonlinear structures associated with characteristic ion populations can occur. Understanding the interaction of the solar wind with the magnetosphere requires a deeper knowledge of the underlying magnetosheath kinetic microstructure. We study a 45 min interval when the MMS spacecraft observed a southward magnetic field (Bz< 0nT) in the dayside magnetosheath. Using magnetic field and plasma data, we analyze three transient dynamic pressure enhancements identified as magnetosheath jets. The characteristics of these jets are different, suggesting different origins. While two of them, called J1 and J2, exhibit large increment in velocity and almost no density increment, the third jet (J3) shows large density enhancements with almost no velocity increment. The duration of J3 is ∼7 times longer than those of J1 and J2. J3 occurs at the region where the negative Bzbecomes positive. Ion distributions inside the jets are different. J1 and J2 show a secondary field‐aligned beam, which is not present in J3, suggesting that magnetic reconnection at the magnetopause is responsible for their formation. Distributions inside J3 are more isotropic. Bfield and plasma signatures inside J3 correspond to the crossing of a sector boundary, similar to the heliospheric plasma sheet, suggesting that J3 forms by the evolution and interaction of a solar wind structure with the bow shock and magnetosheath. Fluctuations inside J3 have larger transverse components, although they propagate at large angles to B. In contrast, waves in regions between the jets are compressive and are identified as mirror mode waves. We study Earth's magnetosheath microstructureWe show that structures identified as jets can be associated with different ion populationsMagnetosheath jets and mirror mode can coexist deep in the magnetosheath

After protons, alpha particles (He++) are the most important ion species in the solar wind, constituting typically about 5% of the total ion number density. Due to their different charge‐to‐mass ratio, protons and He++particles are accelerated differently when they cross the electrostatic potential in a collisionless shock. This behavior can produce changes in the velocity distribution function (VDF) for both species generating anisotropy in the temperature, which is considered to be the energy source for various phenomena such as ion cyclotron and mirror mode waves. How these changes in temperature anisotropy and shock structure depend on the percentage of He++particles and the geometry of the shock is not completely understood. In this paper, we have performed various 2D local hybrid simulations (particle ions, massless fluid electrons) with similar characteristics (e.g., Mach number) to interplanetary shocks for both quasi‐parallel and quasi‐perpendicular geometries self‐consistently including different percentages of He++particles. We have found changes in the shock transition behavior as well as in the temperature anisotropy as functions of both the shock geometry and He++particle abundance: The change of the initial θBnleads to variations of the efficiency with which particles can escape to the upstream region facilitating or not the formation of compressive structures in the magnetic field that will produce increments in perpendicular temperature. The regions where both temperature anisotropy and compressive fluctuations appear tend to be more extended and reach higher values as the He++content in the simulations increases. He++content modifies the shock profile, temperature anisotropy, and distribution functions in the upstream and downstream regionsθBnand He++content affects the efficiency with which particles escape to the upstream regionIncrease in magnetic fluctuations and He++content modify regions with higher temperature anisotropy downstream of quasi‐perpendicular shocks