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Dusty plasmas are electrically quasi-neutral media that, along with electrons, ions, neutral gas, radiation, and electric and/or magnetic fields, also contain solid or liquid particles with sizes ranging from a few nanometers to a few micrometers. These media can be found in many natural environments as well as in various laboratory setups and industrial applications. As a separate branch of plasma physics, the field of dusty plasma physics was born in the beginning of 1990s at the intersection of the interests of the communities investigating astrophysical and technological plasmas. An additional boost to the development of the field was given by the discovery of plasma crystals leading to a series of microgravity experiments of which the purpose was to investigate generic phenomena in condensed matter physics using strongly coupled complex (dusty) plasmas as model systems. Finally, the field has gained an increasing amount of attention due to its inevitable connection to the development of novel applications ranging from the synthesis of functional nanoparticles to nuclear fusion and from particle sensing and diagnostics to nano-contamination control. The purpose of the present perspectives paper is to identify promising new developments and research directions for the field. As such, dusty plasmas are considered in their entire variety: from classical low-pressure noble-gas dusty discharges to atmospheric pressure plasmas with aerosols and from rarefied astrophysical plasmas to dense plasmas in nuclear fusion devices. Both fundamental and application aspects are covered. [ABSTRACT FROM AUTHOR]

Background: In this study, we investigate the number of emergency room consultations during the COVID-19 pandemic of 2020 in Germany compared to figures from the previous year. Methods: Case numbers from calendar weeks 1 through 22 of the two consecutive years 2019 and 2020 were obtained from 29 university hospitals and 7 non-university hospitals in Germany. Information was also obtained on the patients' age, sex, and urgency, along with the type of case (outpatient/inpatient), admitting ward, and a small number of tracer diagnoses (I21, myocardial infarction; J44, COPD; and I61, I63, I64, G45, stroke /TIA), as well as on the number of COVID- 19 cases and of tests performed for SARS-CoV-2, as a measure of the number of cases in which COVID-19 was suspected or at least included in the differential diagnoses. Results: A total of 1 022 007 emergency room consultations were analyzed, of which 546 940 took place in 2019 and 475 067 in 2020. The number of consultations with a positive test for the COVID-19 pathogen was 3122. The total number of emergency room consultations in the observation period was 13% lower in 2020 than in 2019, with a maximum drop by 38% coinciding with the highest number of COVID-19 cases (calendar week 14; 572 cases). After the initiation of interpersonal contact restrictions in 2020, there was a marked drop in COVID-19 case numbers, by a mean of -240 cases per week per emergency room (95% confidence interval [-284; -128]). There was a rise in case numbers thereafter, by a mean of 17 patients per week [14; 19], and the number of cases of myocardial infarction returned fully to the level seen in 2019. Conclusion: In Germany, the COVID-19 pandemic led to a significant drop in medical emergencies of all kinds presenting to the nation's emergency departments. A recovery effect began to be seen as early as calendar week 15, but the levels seen in 2019 were not yet reached overall by calendar week 22; only the prevalence of myocardial infarction had renormalized by then. The reasons for this require further investigation. [ABSTRACT FROM AUTHOR]

The potential and density structure behind a spherical microparticle in a magnetized ion flow are studied by means of molecular dynamics simulations. It is shown that, with increasing magnetization of the flow, the ion accumulation in the wake diminishes. Instead, ion depleted regions (shadows) form and ions accumulate at the edge of the shadows. The change of the ion density distribution also affects the force on other microparticles in the downstream region. For weak magnetization and a short distance, these interparticle forces can be attractive and non-reciprocal, as in the unmagnetized case. For large magnetization and further downstream, the force becomes repulsive. The mechanism of shadow formation is shown to involve a fast Coulomb scattering during a short fraction of the gyroperiod and subsequent trapping of the ions on large-radius gyro-orbits. [ABSTRACT FROM AUTHOR]

The influence of velocity spread and ion-neutral collisions on the wake of a microparticle in a collisional magnetized ion flow is explored by means of molecular dynamics simulations. The ion flow is described in the constant-mean-free-path limit. A constant electric field is superimposed that maintains the ion drift at the Bohm speed and approximates conditions in the plasma sheath. The contribution of ion Landau damping to the wake structure is separated by simulations with a collisionless drift distribution. It is found that ion Landau damping and collisions have a counteracting effect on the ion density in the focus region. The dynamic shadows that are a typical feature of collisionless magnetized wakes with cold ion beams are damped by the velocity spread and vanish by a collision-enhanced ion density in the wake. Dynamic shadows reappear only at very high magnetic fields, B ≈ 10 T. In two-particle arrangements, the full collisional model shows that horizontal attractive forces persist up to B = 4 T but become repulsive for higher magnetization. [ABSTRACT FROM AUTHOR]

This article examines narratives of European history from 1914 to 1945 and on European integration published between 1945 to 2016. It discusses the role of Interbellum and national socialism in the history of European idea, historical research into the origins of European though on an international level, and reasons why the age of World Wars was either ignored by early European historiography or marginalized.

The potential and density wake behind a finite-sized object in a magnetized collisionless plasma flow is studied with self-consistent numerical simulations. With increasing magnetization of the plasma, the standard picture of ion focusing in the wake for plasmas with large electron to ion temperature ratios becomes invalid. A strong magnetic field parallel to the flow direction leads to a chain of ion depletions in the wake and enhanced ion density at their envelopes. This is due to a novel mechanism of a dynamic ion shadow, which is not the geometrical shadow of the finite-sized object. It corresponds to a change in topology of the wake potential. Complex ion trajectories resulting from electrostatic collisions with the object can lead to significant variations in electrical charging of other objects in the wake. [ABSTRACT FROM AUTHOR]

Nanoparticles grown in reactive plasmas and nanodusty plasmas gain high interest from basic science and technology. One of the great challenges of nanodusty plasmas is the in-situ diagnostic of the nanoparticle size and refractive index. The analysis of scattered light by means of the Mie solution of the Maxwell equations was proposed and used as an in-situ size diagnostic during the past two decades. Today, imaging ellipsometry techniques and the investigation of dense, i.e., optically thick nanoparticle clouds demand for analysis methods to take multiple scattering into account. We present the first 3D Monte-Carlo polarized radiative transfer simulations of the scattered light in a dense nanodusty plasma. This technique extends the existing diagnostic methods for the in-situ analysis of the properties of nanoparticles to systems where multiple scattering cannot be neglected. [ABSTRACT FROM AUTHOR]

A cryogenic stopping cell (CSC) has been commissioned with 238U projectile fragments produced at 1000 MeV/u. The spatial isotopic separation in flight was performed with the FRS applying a monoenergetic degrader. For the first time, a stopping cell was operated with exotic nuclei at cryogenic temperatures (70 to 100 K). A helium stopping gas density of up to was used, about two times higher than reached before for a stopping cell with RF ion repelling structures. An overall efficiency of up to 15%, a combined ion survival and extraction efficiency of about 50%, and extraction times of 24 ms were achieved for heavy α-decaying uranium fragments. Mass spectrometry with a multiple-reflection time-of-flight mass spectrometer has demonstrated the excellent cleanliness of the CSC. This setup has opened a new field for the spectroscopy of short-lived nuclei. [ABSTRACT FROM AUTHOR]

This paper presents different low-temperature and high-throughput LIGA-like processes for the batch fabrication of metal micro systems that use long nano- or microwires perpendicularly rising from a substrate. First, circuit paths and seed layers are fabricated applying standard UV lithography and PVD. Second, three lithography techniques are used, namely ion track lithography, enhanced UV lithography and aligned x-ray lithography, to structure 20-400 im thick polymer films. Ion track lithography is only used to fabricate extremely high aspect ratio cylindrical pores with 0.1-1 im diameter and 20-100 im length. The aligned UV and x-ray lithographies are employed to structure templates for various micro system components. Third, these polymer templates are filled using low-temperature electroplating processes transferring the polymer openings into metal structures. Finally, the polymer is dry etched to release all metal structures. These structures are applicable in future accelerometers and gas flow sensors. Using five configurations to define five different functional structures, we demonstrate fabrication processes applying the three different types of lithography. The main aspects concern the combination of both standard lithography techniques and especially developed lithography techniques. Furthermore, these aspects comprise the use of structures created by lithography for high aspect ratio polymer templates and multilayer electroplating with varying aspect ratios. The growth in place of nanowire arrays and micropillars along with surrounding structures is the key feature for low-temperature large-scale micro-nano integration technology without harmful transfer technologies [ABSTRACT FROM AUTHOR]

The formation of wake fields downstream of an objects in flowing plasmas has strong implications on structure, stability and dynamics of complex plasmas. This paper aims at putting recent experimental investigations and different theoretical approaches on charging of dust grains, stability of dust grain arrangements and the dynamical properties of complex plasmas into perspective. Further, the combination of wake fields and grain confinement is discussed, which is the generic situation in complex plasmas. It is shown that in spherical traps the resulting competition of trap geometry and vertical alignment leads to a sophisticated mixture of nested shell and string order (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

An overview is given of the confinement and dynamical phenomena observed in experiments and simulations of magnetized dust tori. Due to the presence of gravity, a strongly inhomogeneous velocity field is found along the circumference of the torus. The simulations show that the dust flow, which is unsheared and nearly incompressible, exhibits a distinct shell structure, which can be understood by rapid frictional cooling and strong Coulomb coupling. At lower frictional damping, the symmetry of the flow can be spontaneously broken, leading to a region of strong velocity shear and excitation of Kelvin-Helmholtz instabilities. New experimental evidence of counterflows is found (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The main effect of dust on drift wave turbulence is the enhancement of the nonadiabaticity. Previous work found that nonmodal behavior is important in the nonadiabatic regime of the drift wave system. Here, the modal and nonmodal properties of the linear Hasegawa–Wakatani system of dusty plasmas are investigated. The non-normality of the linear evolution operator can lead to enhanced transient growth rates compared to the modal growth rates. [ABSTRACT FROM AUTHOR]

The scalings of correlation lengths and times with the drift-scale parameter ρs and other dimensionless parameters are investigated. Using a novel 8×8 Langmuir probe matrix, the two-dimensional structure of drift-wave turbulence has been measured inside the confinement region of the toroidal low-temperature plasma in the TJ-K torsatron [N. Krause et al., Rev. Sci. Instrum. 73, 3474 (2002)]. Using five different gases from hydrogen to argon, ρs could be varied by a factor of 10. For small ion masses, the scalings of the microscopic parameters turn out to be close to the predictions from drift-wave turbulence, which lead to a gyro-Bohm scaling of the diffusivity. Including heavier ions turns the scaling to more Bohm-like. It is shown that ρs scaling studies carried out on the diffusivity can be misleading if residual dependencies on other parameters are present and the cross phase between poloidal electric field and density fluctuations is not constant as in the present case. The measured turbulent diffusivity is consistent with typical values reported for the edge of fusion plasmas. [ABSTRACT FROM AUTHOR]

Comparative studies between a toroidal low-temperature plasma and drift-Alfvén-wave simulations were carried out in order to investigate the microscopic structure of turbulence. The dimensionless plasma parameters in the TJ-K torsatron [N. Krause et al., Rev. Sci. Instrum. 73, 3474 (2002)] are similar to those in the edge of a fusion plasma. At the same time the fluctuations can be fully diagnosed by probe arrays. Fluctuation spectra are analyzed by wavelet techniques indicating a large amount of intermittency in both numerical and experimental data. Since in both cases no critical gradient is present, the intermittency is not due to a state in self-organized criticality (SOC). The spectral density P(ω,k) of the turbulence was measured with a 64-tip Langmuir probe array. A broad spectrum indicates fully developed turbulence. The wave-number spectrum of the density fluctuations decays with a power law with an exponent of 23. The experiments confirm predictions from the turbulence code. The cross-phase between potential and density fluctuations is close to zero on all scales and the spectra shift to smaller wave numbers when the drift scale ρs is increased by changing the ion mass from hydrogen to helium and argon. The ρs scaling is confirmed by correlation measurements within the tips of the poloidal array and an 8×8 probe matrix. The results point to the drift-wave mechanism being responsible for the drive of the turbulence in the low-β plasma of TJ-K. [ABSTRACT FROM AUTHOR]

Objective: Intravenous recombinant tissue plasminogen activator (rt-PA) is the only therapy of proven value for patients with acute ischemic stroke (AIS). Controversy exists with regard to the prognostic significance of early computed tomography (CT) changes in patients receiving rt-PA for AIS. The authors retrospectively reviewed all cases of AIS who received intravenous rt-PA for AIS in University of South Alabama hospitals between January 1996 and May 1999. A neuroradiologist, blinded to clinical outcomes, reviewed all baseline CT scans for the presence of the following signs: hyperdense middle cerebral artery (HMCA), loss of gray-white differentiation (LGWD), insular ribbon sign (IRS), parenchymal hypodensity (PH), and sulcal effacement (SE). Modified Rankin Scale (mRS) score was recorded 90 days after thrombolysis, and clinical outcome was dichotomized as favorable (0-1) or unfavorable (2-6). The authors performed both univariate and multivariate analyses to investigate the relationship between early CT signs, baseline clinical variables, and functional outcome as measured by the 90-day mRS scores. Any one early CT finding was detected in 23(64%) patients. The frequency of specific findings were as follows: SE in 13 patients (36%), LGWD in 12 patients (33%), PH in 9 patients (25%), HMCA in 4 patients (11%), and IRS in 3 patients (8%) patients. There was no statistically significant association between the occurrence of these imaging findings and subsequent functional outcome after thrombolysis. The data suggest that the presence of subtle acute CT changes in AIS patients is not predictive of clinical outcome following administration of rt-PA as per National Institute of Neurological Disorders and Stroke protocol. [ABSTRACT FROM AUTHOR]

Investigates strongly nonlinear relaxation oscillations of discharge current and plasma potential in a magnetized thermionic plasma discharge. Direct comparison with one-dimensional models and computer simulations; Nonlinear instability of the potential structure in the weak current discharge mode.

Investigates the discharge modes of a thermionic low pressure discharge with the one-dimensional particle-in-cell simulation codes PDP1 and XPDP1. Model approach for stable discharge modes, nonlinear structures, hysteresis, and for nonlinear relaxation-oscillations; Suggestion of a Pierce-Buneman-mode as a trigger mechanism for the onset of instability.