Shock Waves In Plasma Research Articles

Head on collision of ion–acoustic shock waves in weakly relativistic electron–positron–ion quantum plasma

In this work, we explore analytically the head on collision (HoC) of two ion acoustic shock wave in relativistic quantum plasma. Extended Poincaré Lighthill Kuo(PLK) method has been applied in this problem in a fruitful manner to study the HoC of waves which are rare in literature. Introducing the strained coordinates and expanding the field quantities into the parameter ϵ, a set of differential equations is obtained. Tangent Hyperbolic method is also used while investigating nonlinear interaction of this mode. These techniques are proven to be efficient enough to extract the essence of physics. Our major focus is to study the influence of plasma characteristics on shock wave phase shifts upon a head-on collision. The effects of the ratio of electrons to positron temperature, fractional concentration of positrons, quantum parameter, kinematic viscosity on the phase shift are studied. The findings suggest that shock interactions are distinct from those of solitons. It is also observed that the dispersion and dissipation of the colliding nonlinear structure have a combined role in the occurrence and modification of trajectory variations. The results of this work might be beneficial in studying the propagation and interaction of quantum ion–acoustic shock waves in dense astrophysical plasma systems (white dwarf star) and intense laser-solid density plasma investigations.

Density jump for oblique collisionless shocks in pair plasmas: allowed solutions

Shock waves in plasma are usually dealt with using magnetohydrodynamics (MHD). Yet, MHD entails the assumption of a short mean free path, which is not fulfilled in a collisionless plasma. Recently, for pair plasmas, we devised a model allowing one to account for kinetic effects within a MHD-like formalism. Its relies on an estimate of the anisotropy generated when crossing the front, with a subsequent assessment of the stability of this anisotropy in the downstream. We solved our model for parallel, perpendicular and switch-on shocks. Here we bridge between all these cases by treating the problem of an arbitrarily, but coplanar, oriented magnetic field. Even though the formalism presented is valid for anisotropic upstream temperatures, only the case of a cold upstream is solved. We find extra solutions which are not part of the MHD catalogue, and a density jump that is notably less in the quasi-parallel, highly magnetized, regime. Given the complexity of the calculations, this work is mainly devoted to the presentation of the mathematical aspect of our model. A forthcoming article will be devoted to the physics of the shocks here defined.

Linear analysis and head-on collision of dust ion-acoustic shock waves in un-magnetized electronegative collisional plasmas

The linear properties and head-on collision of dust ion-acoustic shock waves (DIASWs) are investigated in un-magnetized electronegative collisional plasmas comprising non-inertial thermal electron and light negative ion, inertial positive ion, and stationary dust grain with negative charges. In this regard, the dispersion relation is derived using the standard normal mode analysis and the two-sided damped Korteweg–deVries (dKdV) equations are derived employing the extended Poincaré Lighthill Kuo (ePLK) method. The effects of physical parameters on linear dispersion relation, formation of shocks, phase shift due to head-on collision, and collision process are studied. It is found that the effect of is more dominant to the wave frequency than that of and in a certain range of the group velocity of the DIASWs is increasing and then decreasing for the effect of the ratio of negative ion to electron density. The amplitude and width of the DIASWs increase with the enhancement of electron temperature and the ion-neutral collision plays a significant role in the formation of shock. The consequence of () the phase shift is increasing (decreasing). The results of this study may be useful to the investigation of space and astrophysical environment where the electronegative collisional plasma exists.

Ultrasound-Guided Autologous Platelet-Rich Plasma Injections Versus Focal Ultrasound-Guided Extracorporeal Shockwave Therapy for Plantar Fasciitis in Athletes and Nonathletes: A Retrospective Comparative Study With Minimum 2-Year Follow-Up

Plantar fasciitis is often cause of heel pain, especially in sporting-related activities. Different conservative measures for the management of plantar fasciitis were compared in several researches. The purpose of this retrospective study was to evaluate and compare clinical outcomes of chronic plantar fasciitis treated with ultrasound-guided platelet-rich plasma (PRP) and focal ultrasound-guided extracorporeal shockwave therapy (ESW). Secondarily, results on subpopulation of athletes were recorded. Fifty-five patients treated for plantar fasciitis were included, 24 among them were competitive or recreational athletes. Treatment outcomes were assessed using Visual Analog Scale and Foot Function Index before and after treatment. Time to return to sport among patients practicing sporting activities was recorded. Before treatment, no differences were observed between groups in terms of age, gender, body mass index, and months of follow up. From baseline to final follow-up assessment, significant improvement was observed in all the outcomes measures. The subgroup analysis showed no differences between patients stratified for type of treatment and sport/nonsport practitioners. The overall failure rate was higher, although not significant, in patients who underwent ESW therapy and they required a higher number of orthopedic visits. Among sports practitioners the mean time to return to sport (months) was faster in PRP group than ESW group (p = .044). PRP and ESW represent both reliable solutions for plantar fasciitis leading to good results in terms of patients’ satisfaction, pain, and clinical outcomes. However, after treatment with PRP injections less recurrences in overall population and faster return to sporting activities in sports practitioners were observed.

Conservative Treatments for Patellar Tendinopathy: A Review of Recent High-Quality Evidence

Patellar tendinopathy is a common injury characterized by progressive activity-related anterior knee pain. It is highly prevalent in sports which involve jumping and changing direction. The aim of this paper is to review recent high-quality evidence regarding the effectiveness of physical therapy in the treatment of patellar tendinopathy. Randomized controlled trials (n = 22) researching the effects of exercise therapy, physical agents, and soft tissue techniques were included. The results show that exercise therapy is the most effective. While eccentric exercise is commonly used, very promising progressive tendon-loading exercise therapy programs are recently emerging. Extracorporeal shock wave therapy, dry needling, and orthoses are no more effective than eccentric exercises or placebo groups. Isometric and isotonic exercise, patellar strap, sports tape, and kinesiotaping have a short-term effect on functional improvement and pain reduction, while progressive tendon-loading exercise, dry needling, platelet-rich plasma, and extracorporeal shock wave therapy have long-term effects.

Synergistic effects of autologous platelet-rich plasma combined with an extracorporeal shock wave in treatment of long diaphysis aseptic nonunion

IntroductionUnion of long bone fractures is a complicated biological mechanism affected by numerous systemic and local variables. Disruption of any of these components may result in fracture nonunion. There are various types of clinically available treatment strategies for aseptic nonunion. Both activated platelet plasma and extracorporeal shock waves play important roles in fracture healing. This study aimed to investigate the interaction of platelet-rich plasma (PRP) and extracorporeal shock wave (ESW) in bone healing of nonunion. HypothesisPRP and ESW have synergistic effects in treating long bone nonunion. MethodsBetween January 2016 and December 2021, a total of 60 patients with established nonunion of a long bone (18 tibias, 15 femurs, 9 humerus, 6 radii, and 12 ulnae) were included in this study, comprising 31 males and 29 females, ranging from 18 to 60 years old. Patients with bone nonunion were separated into two groups: PRP alone (Monotherapy group) and those treated with PRP combined with ESW (Combined treatment group). The two groups were compared to assess the therapeutic benefits, callus development, local problems, bone healing time, and Johner Wruhs functional classification of operated limbs. ResultsFifty-five patients were followed up, 5 patients were lost to follow-up, two in the PRP group and three in the PRP+ESW group, the follow-up time varied from 6 to 18 months, with an average of 12.7±5.2 months. At 8, 12, 16, 20, and 24 weeks following intervention, the callus score in the monotherapy group was significantly lower than in the combined treatment group (p<0.05). Both groups had no swelling and infection in the soft tissue of the nonunion operation site. In the PRP+ESW group, the fracture union rate was 92.59% and the healing time was 16.3±5.2 weeks. In the PRP group, the fracture union rate was 71.43% and the healing time was 21.5±3.7 weeks. The clinical healing time of the monotherapy group was significantly longer than the combined treatment group (p<0.05). All the nonunion patients with no signs of healing were treated with revision surgery. The excellent and good rate of Johner-Wruhs functional classification of affected limbs in the monotherapy group was significantly lower than in the combined treatment group (p<0.05). ConclusionPRP combined with ESW has a certain synergistic effect in treating aseptic nonunion after fracture surgery. It can significantly improve the formation of new bone, it is a minimally invasive and effective strategy to treat aseptic nonunion in a clinical setting. Level of evidenceIII, retrospective, single-centre, case-control study.

Mechanism in damage variation of nanosecond laser-induced damage of germanium sheets in vacuum

Laser-induced damage of germanium (Ge) sheets plays a key role to estimate the lifetime of optical components in the vacuum and space irradiation environment. However, the dependence between the degrees of laser-induced surface damage and nanosecond pulsed irradiation remains unclear for Ge sheet. Here, we investigate damage morphology and the growth characteristic of Ge sheets under different conditions and measure the laser-induced damage threshold (LIDT) in vacuum. Our results reveal that optical reflectivity of Ge in vacuum chamber falls 92% because of the defective sites on the damaged surface. The area, the depth and the size of the damage crater increase but the hillock height and the surrounding thermal diffuse area decrease along with the increase of vacuum degree. The thermal effect, the failure effect of plasma shock wave and the mechanical stress are analyzed to be the main mechanism in the laser damage. The combined experimental and theoretical work gives an insight into the change of surface damage and material failure behavior, hence broadens the potential applications of Ge sheets in areas of laser material manufacturing and laser processing.

Evolution of ion-acoustic shock waves in magnetized plasma with hybrid Cairns–Tsallis distributed electrons

Abstract The propagation of nonlinear electrostatic ion-acoustic (IA) shock waves in presence of external magnetic field having Cairns–Tsallis distributed electrons and ion kinematic viscosity is investigated. In the linear regime, the dispersion relation of the ion acoustic shock wave is found to be modified by the external magnetic field. Adopting reductive perturbation approach, it is shown that the dynamics of shocks is modeled by a hybrid Ostrovsky–Burgers’ equation. The influence of relevant physical parameters such as nonthermality and nonextensivity of electrons, magnetic field strength, and ion kinematic viscosity on the time evolution of the shock structure is numerically examined. It is observed the present plasma system supports both compressive and rarefactive shock waves. Furthermore, the analysis is performed through dynamical system approach to elucidate the various aspects of the phase-space shock dynamics.

Nonlinear behaviour of ion acoustic shock waves in a two-electron temperature nonthermal complex plasma

Abstract The nonlinear propagation of dust-ion-acoustic shock waves (DIASWs) in unmagnetized dusty plasma comprising inertial ions, non-Maxwellian electrons with two distinct temperatures, and negatively charged dust is investigated in this article using a different approach based on the Sagdeev pseudopotential theory. The reductive perturbation approach is used to produce the KdVB and mKdVB equations and a comparison of their analytical and numerical solutions is shown. The effects of various parameters consisting of macroscopic non-thermal, ion-kinematic viscosity, etc. that significantly alternate the qualitative properties of DIASW are discussed. Both oscillatory and monotonic natures of the dispersive-diffusive shock wave structures are described in the present study. It has also been concentrated on nonlinear dynamics in such a plasma environment. The findings of this study should aid in understanding the nonlinear dynamics of wave damping and interactions in space and laboratory dusty plasmas, where the most relevant plasma parameters are kinematic viscosity and macroscopic non-thermality.

Dynamics of laser-induced phase transformation in bulk of monocrystalline sapphire

Transient effects during and after the optical breakdown initiated by an intense sub-nanosecond laser pulse in bulk of monocrystalline sapphire were investigated using ultrafast time-resolved microscopy. The method provided direct quantitative information about temporal evolution of the laser-induced plasma channel as well as spatio-temporal characterization of the shock-waves. It was found that plasma channel evolved according to the classical model of moving breakdown, but in the initial phase there were signs of the laser-supported absorption wave (LSAW). The estimated maximum of the of absorption wave velocity in sapphire reached 340 km/s to decrease quickly to 53 km/s in the moment when the shock wave was emerged for the first time. At the final state of propagation, the front of the shock wave has converted to a spherical shape moving with a speed very close to the speed of acoustic wave in sapphire. The evolution of radii of the plasma channel and shockwave front were reasonably well fitted with the Sedov’s scaling rule. The structural analysis of the post-irradiated site showed phase-transitions from single crystal to a polycrystalline or amorphous phase but only very close to the void walls.

Nonlinear self-adjointness, conserved quantities and Lie symmetry of dust size distribution on a shock wave in quantum dusty plasma

The current exploration explains new traveling wave profiles by the Lie symmetry approach Here, we derive the (3+1)-dimensional Zakharov–Kuznetsov burgers equation for the shock wave phenomena in plasma with dust-charged particles having quantum effects. The structures of this model are made by Abelian algebra. The considered equation is reduced to an ordinary differential equation by the use of this Abelian algebra. The complete derivation of the classical symmetries of the considered model and reduction corresponding to the first four symmetries has been added. The new auxiliary equation method is implemented for the formation of the new traveling wave structures. The graphical explanation of some obtained results are elaborated in detail. The nonlinear self-adjointness of the considered model is also part of this work. By this concept, we have evaluated the conservation laws of the model. This work is new and does not exist in literature.

Immunophenotypic characteristics of the fibrous component of the blood-testis barrier when using cell therapy for azoospermia treatment

Objective. Immunohistochemistry testicular tissue collagens evaluation in the treatment of azoospermia with platelet-rich plasma (PRP) and extracorporeal shock wave therapy (ESWT).Materials and methods. We used biopsy material of testicular fragments from 14 patients with an established diagnosis of secretory azoospermia before and after the use of PRP plus ESWT (patent granted RU2738543 from 14.12.2020). The mean age was 33.07 ± 4.64 (28–43 years), the mean duration of the disease – 4,1 ± 2,26 years (1–9 years). All participants received 2 therapy sessions per week during 6 weeks. 1st session included ultrasound-guided PRP injections into testicles and spermatic cords, finally PRP was activated with ESWT (Dornier Aries), 2nd session included ESWT per testicles and epididymis. Immunohistochemistry analysis with antibodies to collagen types I, III and IV of patient’s biopsies with azoospermia were completed on 90 days before treatment and 180 days from last PRP-injection.Results. Before PRP and ESWT therapy: type I collagen was 22.9 ± 4.2 % (p &lt;0.05), type III collagen – 7.3 ± 2.2 % (p &lt;0.05), type IV collagen – 21.4 ± 1.5 % (p &lt;0.05); after combined therapy: type I collagen – 27.3 ± 5.7 % (p &lt;0.05), type III collagen – 7.2 ± 1.5 % (p &lt;0.05), type IV collagen – 32.2 ± 2.6 % (p &lt;0.05).Conclusion. The production of biologically active substances against the background of PRP and ESWT therapy stimulates the collagen various types synthesis, which promotes to the restoration of the fibrous component of the blood-testicular barrier and improves spermatogenesis.

Plasma Shock Wave in Gamma-Ray Bursts: Nonlinear Phenomena and Radiative Process

Since gamma-ray bursts (GRBs) are related to extreme explosions in the universe, they provide a unique setup to study various space plasma phenomena. The GRB spectra supply a wide range of information regarding the various nonlinear interactions and associated structures. In this work, we study the generation of shock fronts and their properties in a plasma. Such a plasma shock is the aftereffect of an explosion of which the prompt emission of GRBs are the signatures. The shock fronts are studied analytically by deriving the KdV–Burger’s equation. The solution of the KdV–Burgers equation via the “Cole-Hoff transformation” is studied alongside the usual “hyperbolic-tangent method.” The dynamical properties of the shock solitons are studied further to second our findings and find the stability and any possibility of chaos. The results will help to interpret the stellar plasma properties from data. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">PACS</i> —95.30.Qd, 52.65.-y, 52.35.-g, 52.35.Tc, 52.27.Lw

65 - Erectile dysfunction treatment by platelet-rich plasma and extracorporeal shock wave therapy

65 - Erectile dysfunction treatment by platelet-rich plasma and extracorporeal shock wave therapy

Discrete Boltzmann modeling of plasma shock wave

Plasma shock waves widely exist and play an important role in high-energy-density environment, especially in the inertial confinement fusion. Due to the large gradient of macroscopic physical quantities and the coupled thermal, electrical, magnetic, and optical phenomena, there exist not only hydrodynamic non-equilibrium (HNE) effects but also strong thermodynamic non-equilibrium (TNE) effects around the wavefront. In this work, a two-dimensional single-fluid discrete Boltzmann model is proposed to investigate the physical structure of ion shock. The electron is assumed inertialess and always in thermodynamic equilibrium. The Rankine–Hugoniot relations for single-fluid theory of plasma shock wave is derived. It is found that the physical structure of shock wave in plasma is significantly different from that in normal fluid and somewhat similar to that of detonation wave from the sense that a peak appears in the front. The non-equilibrium effects around the shock front become stronger with increasing Mach number. The charge of electricity deviates oppositely from neutrality in upstream and downstream of the shock wave. The large inertia of the ions causes them to lag behind, so the wavefront charge is negative and the waverear charge is positive. The variations of HNE and TNE with Mach number are numerically investigated. The characteristics of TNE can be used to distinguish plasma shock wave from detonation wave.

Obliquely propagating dust acoustic shock waves in magnetized plasma under the influence of polarization force and nonadiabaticity of dust charge variation

In this work, we have analyzed the impact of polarization force, angle of obliqueness under the influence of nonadiabatic dust charge fluctuation on shock waves formation in magneto rotating plasma. The present plasma model is consisting of negatively charged dust grains, Maxwellian electrons, non-Maxwellian hybrid distributed ions. The dissipation is introduced in the system via nonadiabaticity, a new mechanism for the formation of shock waves. Using the standard reductive perturbation method, nonlinear equation, namely, Korteweg-de Vries-Burgers (KdVB) equation is derived and solution is obtained using the Tanh method. It is shown that dust charge fluctuation is the main source of dissipation. We have studied the various parameteric influences on such shock structure and also showed how the gradual variations of these parameters affect the generation and structure of the shocks in their respective domain. Much of the experiments on dusty plasma with nonadiabatic dust charge fluctuation will benefit from the parametric study.

Theory and simulations of field strengths in magnetosonic shock waves in finite beta plasmas

Field strengths in an oblique magnetosonic shock wave in a collisionless, finite beta plasma are studied with theory and simulations. With the use of the warm, two-fluid model, the maximum values of the magnetic field, the transverse electric field, and the electric potential in a shock wave are analytically obtained as functions of the shock speed. One-dimensional, electromagnetic particle simulations are then carried out to measure the field strengths in shock waves. The theory and the simulation results are found to be consistent.

Electrostatic Shock Structures in a Magnetized Plasma Having Non-Thermal Particles

A rigorous theoretical investigation has been made on the nonlinear propagation of dust-ion-acoustic shock waves in a multi-component magnetized pair-ion plasma (PIP) having inertial warm positive and negative ions, inertialess non-thermal electrons and positrons, and static negatively charged massive dust grains. The Burgers’ equation is derived by employing the reductive perturbation method. The plasma model supports both positive and negative shock structures in the presence of static negatively charged massive dust grains. It is found that the steepness of both positive and negative shock profiles declines with the increase of ion kinematic viscosity without affecting the height, and the increment of negative (positive) ion mass in the PIP system declines (enhances) the amplitude of the shock profile. It is also observed that the increase in oblique angle raises the height of the positive shock profile, and the height of the positive shock wave increases with the number density of positron. The applications of the findings from the present investigation are briefly discussed.

Large-Scale Black Silicon Induced by Femtosecond Laser Assisted With Laser Cleaning

Black silicon is a promising and effective candidate in the field of photoelectric devices due to the high absorptance and broad-spectrum absorption property. The deposition around the processing area induced by the pressure of SF6, gravity, and the block of the processing chamber interferes the adjacent laser ablation and hampers uniform large-scale black silicon fabrication. To solve the problem, femtosecond laser- induced black silicon assisted with laser plasma shockwave cleaning is creatively proposed in our study. The results showed that higher, denser, and more uniform microstructures can be obtained than the conventional laser-induced method without laser cleaning. The average absorptance is 99.15% in the wavelength range of 0.3–2.5 µm, while it is more than 90% in the range of 2.5–20 µm. In addition, the scanning pitch dependence of surface morphology is discussed, and the better result is obtained in the range of 25–35 µm with 40-µm laser spot. Finally, a large-scale 50-mm × 50-mm black silicon with uniform microstructures was prepared by our method. It has been demonstrated that the deposition is effectively eliminated via our method, and the optical absorption is also enhanced significantly. It is of great significance for realizing large-scale preparation of photoelectric devices based on black silicon and lays the foundation for the development of laser-inducing equipment and industrial application.

Mechanism Analysis of Rock Failure Process under High-Voltage Electropulse: Analytical Solution and Simulation.

This work aims to investigate and analyse the mechanism of rock failure under high-voltage electropulses in order to evaluate and increase the efficiency of high-voltage pulse technology in geological well drilling, tunnel boring, and other geotechnical engineering applications. To this end, this paper discusses the equivalent circuit of electric pulse rock breaking, the model of shock wave in electro channel plasma, and, particularly, the model of rock failure in order to disclose the rock failure process when exposed to high-voltage electropulse. This article uses granite as an example to present an analytical approach for predicting the mechanical behaviour of high-voltage electropulses and to analyse the damage that occurs. A numerical model based on equivalent circuit, shock wave model, and elasto-brittle failure criterion is developed for granite under electropulse to further examine the granite failure process. Under the conditions described in this study, and using granite as an example, the granite is impacted by a discharge device (Marx generator) with an initial voltage U0 that is 10 kV and a capacitance F that is 5 µF before it begins to degrade at about 40 µs after discharge, with the current reaching its peak at approximately 50 µs. The shock wave pressure then attains a peak at about 70 µs. Dense short cracks form around granite and the dominant cracks grow to an average length of about 20 cm at around 200 µs. The crack width dcr is predicted to be approximately 1.6 mm. This study detects dense cracks in a few centimetres surrounding the borehole, while around seven dominant cracks expand outward. The distribution of the length of the dominating cracks can be inhomogeneous because of the spatial heterogeneity of granite’s tensile strength, however the heterogeneity has an insignificant effect on the crack growth rate, total cracked area, or the number of main cracks. The mechanism of rock failure under electropulse can be well supported by the findings of numerical simulations and analytical studies.