scholarly journals Acceleration and transport of ions in turbulent current sheets: formation of non-maxwelian energy distribution

2009 ◽  
Vol 16 (6) ◽  
pp. 631-639 ◽  
Author(s):  
A. V. Artemyev ◽  
L. M. Zelenyi ◽  
H. V. Malova ◽  
G. Zimbardo ◽  
D. Delcourt
Keyword(s):  
Electric Field ◽  
Particle Interaction ◽  
Average Energy ◽  
Average Particle ◽  
Acceleration Of Particles ◽  
Neutral Sheet ◽  
Energy Distributions ◽  
Stationary Turbulence ◽  
Reconnection Region ◽  
Transport Of Ions

Abstract. The paper is devoted to particle acceleration in turbulent current sheet (CS). Our results show that the mechanism of CS particle interaction with electromagnetic turbulence can explain the formation of power law energy distributions. We study the ratio between adiabatic acceleration of particles in electric field in the presence of stationary turbulence and acceleration due to electric field in the case of dynamic turbulence. The correlation between average energy gained by particles and average particle residence time in the vicinity of the neutral sheet is discussed. It is also demonstrated that particle velocity distributions formed by particle-turbulence interaction are similar in essence to the ones observed near the far reconnection region in the Earth's magnetotail.

scholarly journals Liver Radioembolization: a New Chapter in Russian Oncology

2019 ◽  
Vol 29 (5) ◽  
pp. 7-12
Author(s):  
A. D. Kaprin ◽  
S. A. Ivanov ◽  
V. V. Kucherov ◽  
A. P. Petrosyan ◽  
K. V. Mayorov ◽  
...  
Keyword(s):  
Liver Cancer ◽  
Average Energy ◽  
Hepatocellular Cancer ◽  
Beta Particle ◽  
Research Centre ◽  
Gamma Line ◽  
Average Particle ◽  
Liver Tumours ◽  
Number Of Patients ◽  
Yttrium 90

Recent years have seen an increase in the number of patients with malignant tumours of the liver. In this context, new treatment methods are being actively introduced into practice, one of which is liver radioembolization utilizing microspheres embedded with yttrium-90 (90Y).Aim. To review literature data on the history of radioembolization and its application for liver tumours.Key findings. Annually, over 200 thousand patients with inoperable primary liver cancer and over 270 thousand patients with inoperable metastatic liver cancer are registered globally, for whom radioembolization is considered as the most suitable treatment method. 90Y is a pure beta emitter without its own gamma line, which is characterized by a small average particle path in the tissue of 2.5 mm (the maximum level is 11 mm), a maximum beta particle energy of 2.27 MeV (average energy of 0.937 MeV) and a half-life of 64.1 hours. Clinical research into microspheres containing 90Y has been actively conducted since 1977 all over the world. However, it was only in 2004 that the US FDA authorized the clinical use of glass microspheres containing 90Y for the treatment of hepatocellular cancer and liver colorectal cancer metastases. Until recently, radioembolization has not been applied in Russia. In 2018, the joint efforts of the A. Tsyb Medical Radiological Research Centre (MRRC) — branch of the National Medical Research Radiological Centre and BEBIG LLC resulted in the production of Russian microspheres containing yttrium-90, which were subsequently introduced into routine clinical practice. The first liver embolization in Russia using microspheres containing domestic yttrium-90 (BEBIG LLC) to a patient with hepatocellular cancer was carried out by V.V. Kucherov and A.P. Petrosyan at the A. Tsyb RMMC on April, 25 in 2019.Conclusion. The production of microspheres containing 90Y in Russia, as well as a technical improvement of the procedure, will facilitate the introduction of liver radioembolization into the routine management of patients with malignant liver tumours.

scholarly journals Particle Orbits, Trapping, and Acceleration in a Filamentary Current Sheet Model

1994 ◽  
Vol 142 ◽  
pp. 719-728
Author(s):  
Bernhard Kliem
Keyword(s):  
Particle Acceleration ◽  
Electric Field ◽  
Test Particle ◽  
Solar Flares ◽  
Acceleration Of Particles ◽  
Acceleration Process ◽  
Two Dimensional ◽  
Magnetic Island ◽  
Particle Orbits ◽  
Island Dynamics

AbstractTest particle orbits in the two-dimensional Fadeev equilibrium with a perpendicular electric field added are analyzed to show that impulsive bursty reconnection, which has been proposed as a model for fragmentary energy release in solar flares, may account also for particle acceleration to (near) relativistic energies within a fraction of a second. The convective electric field connected with magnetic island dynamics can play an important role in the acceleration process.Subject headings: acceleration of particles — MHD — plasmas — Sun: corona — Sun: flares

scholarly journals Acceleration Processes for Gamma-Ray Bursts

1994 ◽  
Vol 142 ◽  
pp. 869-876 ◽  
Author(s):  
Igor G. Mitrofanov
Keyword(s):  
Particle Acceleration ◽  
Electric Field ◽  
Neutron Stars ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Initial Energy ◽  
Gamma Ray Bursts ◽  
Acceleration Of Particles ◽  
Radiation Mechanisms ◽  
Radiative Pressure

AbstractIs it shown that for those astronomical models of cosmic gamma-ray bursts (GRBs) which are associated with galactic neutron stars (NSs), the initial energy of the outburst could be converted to gamma-rays through processes of particle acceleration. The main emission mechanisms are considered for two basic alternatives, when particles are accelerated either by radiative pressure or by an electric field.Subject headings: acceleration of particles — gamma rays: bursts — radiation mechanisms: nonthermal

ER Properties of a Suspension of Polymer Graft Carbon Black Particles

1999 ◽  
Vol 13 (14n16) ◽  
pp. 1682-1688
Author(s):  
Masayoshi Konishi ◽  
Teruhisa Nagashima ◽  
Yoshinobu Asako
Keyword(s):  
Shear Stress ◽  
Carbon Black ◽  
Electric Field ◽  
Silicone Oil ◽  
Average Particle Size ◽  
Average Particle ◽  
Zero Field ◽  
Average Value ◽  
Time Period ◽  
Micron Size

We newly developed ER particles with sub-micron size. The particle was polymer graft carbon black (GCB1) composed of carbon black particles and a polymer. The average particle size of GCB1 was found to be 81 nm. An ER suspension (ER1) was obtained by mixing GCB1 (30 wt%) with silicone oil (70 wt%). The ER1 showed excellent dispersion stability. Further, GCB1 particles did not settle under centrifuging at 9000G. The zero-field viscosity was 80 mPa·s at 25°C. The kinetic friction coefficient of ER1 was 0.15, while that of the silicone oil used was 0.23. When the electric field of 3 kV/mm (AC 1000 Hz) at the temperature of 25°C and the shear rate of 700 s -1 was applied to ER1, the shear stress of 116Pa was induced. The induced shear stress did not change for a long period of time period. In the temperature range between 25 and 150°C the induced shear stress and the current density were almost constant at any electric field. When 3 kV/mm (AC 50Hz) at 25°C and 700s-1 was applied to ER1, the shear stress of 88Pa was induced but the deviation of the induced shear stress from the average value was pluses and minuses 3 Pa.

scholarly journals On the observed energy of runaway electron beams in air

2011 ◽  
Vol 29 (4) ◽  
pp. 425-435 ◽  
Author(s):  
G.A. Mesyats ◽  
A.G. Reutova ◽  
K.A. Sharypov ◽  
V.G. Shpak ◽  
S.A. Shunailov ◽  
...  
Keyword(s):  
Electric Field ◽  
Runaway Electron ◽  
Electron Beams ◽  
Beam Current ◽  
Acceleration Of Particles ◽  
Runaway Electrons ◽  
Electrode Gap ◽  
Cathode Voltage ◽  
Wide Range ◽  
Widespread Belief

AbstractExperiments with an air electrode gap have been performed where the current/charge of a picosecond beam of runaway electrons was measured over a wide range (up to four orders of magnitude) downstream of the absorbing foil filters. Measurements and calculations have made it possible to refer the beam current to the rise time of the accelerating voltage pulse to within picoseconds. It has been shown that, in contrast to a widespread belief, the runaway electron energies achieved are no greater than those corresponding to the mode of free acceleration of electrons in a nonstationary, highly nonuniform electric field induced by the cathode voltage. The experimental data agree with predictions of a numerical model that describes free acceleration of particles. It has been confirmed that the magnitude of the critical electric field that is necessary for electrons to go into the mode of continuous acceleration of electrons in atmospheric air corresponds to classical notions.

Dynamics of Elementary Processes At Surfaces: Nitric Oxide Scattered From A Graphite Surface

1985 ◽  
Vol 51 ◽  
Author(s):  
H. Vach ◽  
J. Häger ◽  
B. Simon ◽  
C. Flytzanis ◽  
H. Walther
Keyword(s):  
Molecular Beam ◽  
Average Energy ◽  
Solid Surfaces ◽  
Energy Distributions ◽  
Vibrationally Excited ◽  
Molecular Beam Scattering ◽  
Elementary Processes ◽  
Beam Scattering ◽  
Powerful Means ◽  
Energy And Momentum

ABSTRACTMolecular beam scattering from solid surfaces has long been recognized as a powerful means for investigation of gas-surface reaction dynamics. With the help of the recently developed laser-induced fluorescence and ionization techniques for state-selective detection, one can now measure the angular and velocity distributions of the scattered molecules together with their internal energy distributions. Such measurements fully describe the average energy and momentum exchanges between molecules and surfaces and give thus full information on the dynamics of the interaction. Recently, also the scattering of vibrationally excited NO molecules was investigated. The paper gives a review of new experiments with emphasis on the investigation of the scattering of NO molecules from a pyrographite surface. A simple model using transport properties of the solid is presented which accounts surprisingly well for the observed features.

scholarly journals Iterative Dipole Moment Method for the Dielectrophoretic Particle-Particle Interaction in a DC Electric Field

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Qing Zhang ◽  
Kai Zhang
Keyword(s):  
Dipole Moment ◽  
Electric Field ◽  
Moment Method ◽  
Particle Interaction ◽  
Particle Interactions ◽  
Electric Force ◽  
Microfluidic Systems ◽  
Initial Particle ◽  
Connection Line ◽  
Dc Electric Field

Electric force is the most popular technique for bioparticle transportation and manipulation in microfluidic systems. In this paper, the iterative dipole moment (IDM) method was used to calculate the dielectrophoretic (DEP) forces of particle-particle interactions in a two-dimensional DC electric field, and the Lagrangian method was used to solve the transportation of particles. It was found that the DEP properties and whether the connection line between initial positions of particles perpendicular or parallel to the electric field greatly affect the chain patterns. In addition, the dependence of the DEP particle interaction upon the particle diameters, initial particle positions, and the DEP properties have been studied in detail. The conclusions are advantageous in elelctrokinetic microfluidic systems where it may be desirable to control, manipulate, and assemble bioparticles.

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