Electron cyclotron resonance near the axis of a quadrupole linear trap

The quasi-longitudinal propagation of an extraordinary electromagnetic wave in the vicinity of the electron cyclotron resonance layer in an open linear trap with a quadrupole magnetic field is studied analytically, taking into account the inhomogeneity of the magnetic field in a paraxial approximation. The ray trajectories are derived from a simplified dispersion equation, that is, nonetheless able to accurately describe the transition from finite to zero perpendicular refractive index. A criterion for an on-axis resonance point to be an attractor for the ray trajectories is formulated, which generalizes a similar criterion for axisymmetric linear traps derived in a recent paper [D. S. Bagulov and I. A. Kotelnikov, Phys. Plasmas 19, 082502 (2012)]

Equilibrium of charged plasmas with weak axisymmetric magnetic perturbations

The effect of weak axisymmetric magnetic and/or electrostatic perturbations on the equilibrium of a non-neutral plasma in a Malmberg-Penning trap is analyzed. A semi-analytic solution for the potential variations inside the trap is found in a paraxial limit of the perturbations for the case of global thermal equilibrium. The fraction of magnetically and electrostatically trapped particles is calculated for a bi-Maxwellian distribution function

Photon neutralizer as an example of an open billiard

A simple photon cavity consisting of three flat mirrors is considered, which provides a model for a photon neutralizer of negative ion beams to be used in a neutral beam injector for plasma heating in fusion devices. Treating the system as an open mathematical billiard, the mechanism of photon scattering on the sharp boundary between two mirrors is described. Assuming a balance between the continuous injection of the photons into the device and their loss through its open ends, the stationary angular distribution of the photons in the trap is computed in closed form and an estimate for the confinement time of the photons in the neutralizer is provided

Calculation of coherent synchrotron radiation impedance using the mode expansion method

We study an impedance due to coherent synchrotron radiation (CSR) generated by a short bunch of charged particles passing through a dipole magnet of finite length in a vacuum chamber of a given cross section. In our method we decompose the electromagnetic field of the beam over the eigenmodes of the toroidal chamber and derive a system of equations for the expansion coefficients in the series. The general method is further specialized for a toroidal vacuum chamber of a rectangular cross section where the eigenmodes can be computed analytically. We also develop a computer code that calculates the CSR impedance for a toroid of rectangular cross section. Numerical results obtained with the code are presented in the paper

CSR IMPEDANCE DUE TO A BEND MAGNET OF FINITE LENGTH WITH A VACUUM CHAMBER OF RECTANGULAR CROSS SECTION

We study the impedance due to coherent synchrotron radiation (CSR) generated by a short bunch of charged particles passing through a dipole magnet of finite length in a vacuum chamber of a given cross section. Our method represents a further development of the previous studies: we decompose the electromagnetic field of the beam over the eigenmodes of the toroidal chamber and derive a system of equations for the expansion coefficients in the series. We illustrate our general method by calculating the CSR impedance of a beam moving in a toroidal vacuum chamber of rectangular cross section

ПАТОЛОГИЯ ИЛЕОСАКРАЛЬНОГО СОЧЛЕНЕНИЯ У ПАЦИЕНТОВ ПОЖИЛОГО ВОЗРАСТА С БОЛЬЮ В НИЖНЕЙ ЧАСТИ СПИНЫ (НАБЛЮДАТЕЛЬНАЯ ПРОГРАММА «ИОЛАНТА»)

Pain in the lower back is one of the frequent reasons for seeking medical help among people over 60 years of age. The study of this problem is of interest to specialists of various profiles, including neurologists, rheumatologists, orthopedic surgeons and therapists. Purpose — to determine prevalence rate of sacroiliac joint pathology in elderly patients with low back pain (LBP) in conjunction with evaluation of clinical significance of bone resorption and cytokines markers. Materials and Methods.The study was conducted with consecutive inclusion of patients (n = 259) with mean age of 65.5 year old [62.5; 69.5] who addressed the hospital for the first time in calendar year with complaints for low back pain. The authors performed MRI examination of lumbar-sacral spine and sacroiliac joint, assessed transforming growth factor β1 (TGF β1), interleukin (IL) 1β and IL-6, Beta-Crosslaps (β-CrossLaps) criteria, P1NP (N-terminal propeptide of procollagen type I) concentration and deoxypyridinoline (DPD) level. Results. 39.4% of patients older 60 years with low back pain on MRI demonstrated changes in sacroiliac joints with statistically significant higher (p = 0.037) pain level as compared to patients without pathology of sacroiliac joint, as well as higher values of TGF-β1 (p = 0.033), IL-1β (p = 0.028), IL-6 (p = 0.041), β-CrossLaps (p = 0.028), P1NP (p = 0.037) and DPD (p = 0.002). Conclusion. Reported alterations in sacroiliac joint conditioned by degenerative and dystrophic processes are associated with distinctive signs of osteoarthrosis and confirm non-specific inflammation active with bone resorption in patients with low back pain.Актуальность. В условиях реальной клинической практики при обследовании пациентов с болями в ниж-ней части спины практически не учитывается патология крестцово-подвздошных суставов, часто являющих-ся первопричиной болевого синдрома. Расширение представлений о наличии морфологического субстрата, провоцирующего и поддерживающего боль в нижней части спины у пациентов старшей возрастной группы, крайне актуально, так как позволит сформировать новые алгоритмы диагностики и лечения. Цель исследования — изучить распространенность патологии илеосакрального сочленения у пациентов по-жилого возраста с болевым синдромом в нижней части спины во взаимосвязи с оценкой клинической значи-мости маркеров костной резорбции и цитокинов. Материал и методы. Исследование проведено с последовательным включением больных (n = 259) в воз-расте 65,5 [62,5; 69,5] лет, обратившихся впервые в календарном году по поводу боли в нижней части спины. Проведены магнитно-резонансная томография (МРТ) пояснично-крестцового отдела позвоночника и илео-сакрального сочленения. Определено содержание в сыворотке крови трансформирующего фактора роста β1 (TGF-β1), интерлейкинов (IL) 1β и IL-6, показателя β-CrossLaps, P1NP (N-терминальный пропептид проколла-гена 1 типа), уровня дезоксипиридинолина (ДПИД). Результаты. В 39,4% случаев у пациентов старше 60 лет с болью в нижней части спины при МРТ выяв-лены изменения в илеосакральных сочленениях с более высоким уровнем боли (p = 0,037), чем у больных без патологии илеосакрального сочленения, а также более высокими показателями TGF-β1 (p = 0,033), ИЛ-1β (p = 0,028), ИЛ-6 (p = 0,041), β-CrossLaps (p = 0,028), P1NP (p = 0,037) и ДПИД (p = 0,002). Выводы. Выявленные изменения в илеосакральном сочленении у пациентов с болью в нижней части спины обусловлены дегенеративно-дистрофическим процессом и сопровождаются характерными признаками осте-оратроза, а также свидетельствуют о неспецифическом воспалительном процессе на фоне активной костной резорбции