Anomalous Relativistic Emission from Self-Modulated Plasma Mirrors

The interaction of relativistically intense laser pulse with a plasma mirror produces harmonics of the incident frequency co-propagating in the direction of specular reflection due to the plasma mirror surface oscillating with velocity close to the speed of light. This mechanism has shown its potential for realization of a bright source of extreme ultraviolet radiation and attosecond pulses. Here, we reveal an unexpected transition of this well-known process into a new regime of efficient extreme ultraviolet radiation generation. A novel mechanism of relativistic emission of radiation from plasma mirrors is identified with an extraordinary property that instead of following specular reflection, the radiation is emitted in the direction along the plasma mirror surface. With analytical calculations and numerical particle-in-cell simulations, we show that this radiation originates from laser-driven non-linear oscillations of relativistic electron nanobunches that are generated by a plasma surface instability and propagate along the plasma mirror surface.Comment: 6 pages, 3 figure

State-of-the-art trends in the treatment of immune-mediated inflammatory kidney diseases: Translation of the fundamental science into clinical practice. A review

Immune-mediated kidney diseases like glomerulonephritis and tubulointerstitial nephritis are not the most common cause of chronic kidney disease in the population, however the difficulties in their management, as well as a more rapid deterioration of kidney function, compared to diabetes mellitus and hypertension, justify the importance of this problem for internal medicine. Due to the fundamental discoveries in pathology and to the introduction of various methods of laboratory and instrumental investigation in the second half of the XX century substantial progress was made in the diagnostic approaches and treatment of these conditions. State-of-the-art diagnostic approach requires complex evaluation of the clinical, laboratory and morphological data to identify the nosological form of the disease. The accumulation of knowledge in the field of diseases’ pathogenesis led to the revision of the current classification of glomerulonephritis that should be based on the immunopathogenesis of these conditions. The following phenotypes were suggested: autoimmunity-related, autoinflammation-related, alloimmunity-related, infections-related, and monoclonal gammopathy-related. The assessment of disease activity and chronicity in the kidney tissue should be mandatory. Personalized selection of the optimal treatment modality on the basis of the diagnosis, severity, and individual features of the patient is currently possible. The leading trends include rational prescription of glucocorticoids (steroid-sparing regimens) and cytotoxic agents, e.g. cyclophosphamide, as well as the introduction of multitarget regimens that include biologic agents or small molecules selectively suppressing B-cells or various complement pathways. Another mandatory component of treatment on par with immune suppression is nephroprotective therapy, which currently comprises not only traditional renin-angiotensin-aldosterone antagonists, but also endothelin receptor antagonists and sodium-glucose cotransporter-2 inhibitors. Current guidelines emphasize the importance of the non-pharmacological interventions for the implementation of the nephroprotective strategy. Rational combination of the aforementioned approaches allows for the optimization of the management of patients with immune-mediated kidney diseases, although it requires high competencies and strict adherence to the principles of the evidence-based medicine from the healthcare providers

The Effect of Ultrastrong Magnetic Fields on Laser-Produced Gamma-Ray Flashes

Laser produced $gamma$-photons can make an important impact on applied and fundamental physics that require high $gamma$-photon yield and strong collimation. We propose addition of a constant magnetic field to the laser-solid interaction to obtain the aforementioned desired $gamma$-photon properties. The $gamma$-ray flash spatial and spectral characteristics are obtained via quantum electrodynamics particle-in-cell simulations. When the constant magnetic field aligns with the laser magnetic field then the $gamma$-ray emission is significantly enhanced. Moreover, the $gamma$a-photon spatial distribution becomes collimated, approximately in the form of a disk.Comment: 5 pages, 5 figure

Low transverse emittance electron bunches from two-color laser-ionization injection

A method is proposed to generate low emittance electron bunches from two color laser pulses in a laser-plasma accelerator. A two-region gas structure is used, containing a short region of a high-Z gas (e.g., krypton) for ionization injection, followed by a longer region of a low-Z gas for post-acceleration. A long-laser-wavelength (e.g., 5 micron) pump pulse excites plasma wake without triggering the inner-shell electron ionization of the high-Z gas due to low electric fields. A short-laser-wavelength (e.g., 0.4 micron) injection pulse, located at a trapping phase of the wake, ionizes the inner-shell electrons of the high-Z gas, resulting in ionization-induced trapping. Compared with a single-pulse ionization injection, this scheme offers an order of magnitude smaller residual transverse momentum of the electron bunch, which is a result of the smaller vector potential amplitude of the injection pulse

Detecting radiation reaction at moderate laser intensities.

We propose a new method of detecting radiation reaction effects in the motion of particles subjected to laser pulses of moderate intensity and long duration. The effect becomes sizable for particles that gain almost no energy through the interaction with the laser pulse. Hence, there are regions of parameter space in which radiation reaction is actually the dominant influence on charged particle motion

Magnetic reconnection: from MHD to QED

The paper examines the prospects of using laser plasmas for studying novel regimes ofthe magnetic field line reconnection and charged particle acceleration. Basic features ofplasma dynamics in the three-dimensional configurations relevant to the formation of currentsheets in a plasma are addressed by analyzing exact self-similar solutions of the magnetohydrodynamicsand electron magneto-hydrodynamics equations. Then the magnetic fieldannihilation in the ultrarelativistic limit is considered, when the opposite polarity magneticfield is generated in collisionless plasma by multiple laser pulses, in the regime with adominant contribution of the displacement current exciting a strong large-scale electricfield. This field leads to the conversion of the magnetic energy into the kinetic energy ofaccelerated particles inside a thin current sheet. Charged particle acceleration during magneticfield reconnection is discussed when radiation friction and quantum electrodynamics effectsbecome dominant

Dynamics of relativistic laser‑produced plasmas

We present a brief overview of physical processes in a plasma under the action of relativistically strong electromagnetic radiation generated by high-power lasers. Attention is focused on nonlinear waves in a laser plasma for the creation of compact electron accelerators. Then, we address the acceleration of plasma bunches by the radiation pressure of light, which is the most efficient regime of ion acceleration. Coherent hard electromagnetic radiation in the relativistic plasma is generated in the form of high harmonics and/or electromagnetic pulses, which are compressed and intensified after reflection from relativistic mirrors created by nonlinear plasma waves. These processes are of interest in view of the development of novel methods for acceleration of charged particles and the development of sources of bright and hard electromagnetic radiation