Sheared flow of electrons and ions introduces new drift-type modes and instabilities in plasmas with stationary dust

2011 ◽  
Vol 375 (44) ◽  
pp. 3877-3879 ◽  
Author(s):  
H. Saleem
Keyword(s):  
Sheared Flow ◽  
Electrons And Ions ◽  
Stationary Dust

scholarly journals Generalized universal instability: transient linear amplification and subcritical turbulence

2015 ◽  
Vol 81 (5) ◽  
Author(s):  
Matt Landreman ◽  
Gabriel G. Plunk ◽  
William Dorland
Keyword(s):  
Free Energy ◽  
Temperature Gradient ◽  
Density Gradient ◽  
Linear Amplification ◽  
Magnetic Shear ◽  
Plasma System ◽  
Sheared Flow ◽  
Electrons And Ions

In this work we numerically demonstrate both significant transient (i.e. non-modal) linear amplification and sustained nonlinear turbulence in a kinetic plasma system with no unstable eigenmodes. The particular system considered is an electrostatic slab with magnetic shear, kinetic electrons and ions, weak collisions and a density gradient, but with no temperature gradient. In contrast to hydrodynamic examples of non-modal growth and subcritical turbulence, here there is no sheared flow in the equilibrium. Significant transient linear amplification is found when the magnetic shear and collisionality are weak. It is also demonstrated that nonlinear turbulence can be sustained if initialized at sufficient amplitude. We prove that these two phenomena are related: when sustained turbulence occurs without unstable eigenmodes, states that are typical of the turbulence must yield transient linear amplification of the gyrokinetic free energy.

Vortex formation in a non-uniform self-gravitating dusty magnetoplasma

2007 ◽  
Vol 73 (4) ◽  
pp. 591-598
Author(s):  
AISHA IJAZ ◽  
ARSHAD M. MIRZA ◽  
M. AZEEM
Keyword(s):  
Vortex Formation ◽  
Low Frequency ◽  
Boltzmann Distribution ◽  
Stationary Solutions ◽  
Drift Waves ◽  
Sheared Flow ◽  
Electrons And Ions ◽  
Coupling Equations ◽  
Dust Dynamics ◽  
Nonlinear Mode Coupling

AbstractThe dynamics of low-frequency, short-wavelength electrostatic (SWES) drift waves in a self-gravitating, non-uniform, collisional dusty magnetoplasma with equilibrium dust-velocity gradients is studied in the present work. By employing the dust continuity and momentum equations to describe the dust dynamics and Boltzmann distribution for the electrons and ions, we have derived a new set of nonlinear mode coupling equations. In the linear limit, it is found that SWES drift waves are subjected to dissipative instability in the presence of an equilibrium dust sheared flow and self-gravitation effect. On the other hand, in the nonlinear case, it is shown that possible stationary solutions of the nonlinear equations are dipolar vortices.

In situ irradiation effects studies in medium- and high-voltage TEM

1995 ◽  
Vol 53 ◽  
pp. 234-235
Author(s):  
Charles W. Allen
Keyword(s):  
Cross Section ◽  
Particle Flux ◽  
Threshold Value ◽  
High Energy ◽  
Irradiation Damage ◽  
Defect Complexes ◽  
Lattice Position ◽  
Electrons And Ions ◽  
The Masses

With respect to structural consequences within a material, energetic electrons, above a threshold value of energy characteristic of a particular material, produce vacancy-interstial pairs (Frenkel pairs) by displacement of individual atoms, as illustrated for several materials in Table 1. Ion projectiles produce cascades of Frenkel pairs. Such displacement cascades result from high energy primary knock-on atoms which produce many secondary defects. These defects rearrange to form a variety of defect complexes on the time scale of tens of picoseconds following the primary displacement. A convenient measure of the extent of irradiation damage, both for electrons and ions, is the number of displacements per atom (dpa). 1 dpa means, on average, each atom in the irradiated region of material has been displaced once from its original lattice position. Displacement rate (dpa/s) is proportional to particle flux (cm-2s-1), the proportionality factor being the “displacement cross-section” σD (cm2). The cross-section σD depends mainly on the masses of target and projectile and on the kinetic energy of the projectile particle.

The Basic Physical Principles of Ion, Electron, and X-Ray Detectors and Their Application to Microanalysis

1985 ◽  
Vol 43 ◽  
pp. 154-157
Author(s):  
A.J. Tousimis
Keyword(s):  
Ion Beam ◽  
Depth Resolution ◽  
Sample Surface ◽  
High Energy ◽  
X Rays ◽  
X Ray ◽  
Electrons And Ions ◽  
Spatial Depth ◽  
Minimum Surface Area ◽  
Physical Principles

An integral and of prime importance of any microtopography and microanalysis instrument system is its electron, x-ray and ion detector(s). The resolution and sensitivity of the electron microscope (TEM, SEM, STEM) and microanalyzers (SIMS and electron probe x-ray microanalyzers) are closely related to those of the sensing and recording devices incorporated with them.Table I lists characteristic sensitivities, minimum surface area and depth analyzed by various methods. Smaller ion, electron and x-ray beam diameters than those listed, are possible with currently available electromagnetic or electrostatic columns. Therefore, improvements in sensitivity and spatial/depth resolution of microanalysis will follow that of the detectors. In most of these methods, the sample surface is subjected to a stationary, line or raster scanning photon, electron or ion beam. The resultant radiation: photons (low energy) or high energy (x-rays), electrons and ions are detected and analyzed.

Detector strategies for environmental scanning electron microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1296-1297
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
High Vacuum ◽  
Environmental Scanning Electron Microscopy ◽  
Charge Carriers ◽  
Environmental Scanning ◽  
Surface Information ◽  
X Ray ◽  
Detector Electrode ◽  
Electrons And Ions ◽  
Low Energy Electrons ◽  
Environmental Sem

Environmental SEM operate at specimen chamber pressures of ∼20 torr (2.7 kPa) allowing stabilization of liquid water at room temperature, working on rugged insulators, and generation of an environmental secondary electron (ESE) signal. All signals available in conventional high vacuum instruments are also utilized in the environmental SEM, including BSE, SE, absorbed current, CL, and X-ray. In addition, the ESEM allows utilization of the flux of charge carriers as information, providing exciting new signal modes not available to BSE imaging or to conventional high vacuum SEM.In the ESEM, at low vacuum, SE electrons are collected with a “gaseous detector”. This detector collects low energy electrons (and ions) with biased wires or plates similar to those used in early high vacuum SEM for SE detection. The detector electrode can be integrated into the first PLA or positioned at any other place resulting in a versatile system that provides a variety of surface information.

Formation of a sheared flow z-pinch plasma

2001 ◽  
Author(s):  
R. Golingo ◽  
U. Shumlak ◽  
B. Nelson
Keyword(s):  
Pinch Plasma ◽  
Sheared Flow ◽  
Z Pinch

scholarly journals First transmission of electrons and ions through the KATRIN beamline

2018 ◽  
Vol 13 (04) ◽  
pp. P04020-P04020 ◽  
Author(s):  
M. Arenz ◽  
W.-J. Baek ◽  
M. Beck ◽  
A. Beglarian ◽  
J. Behrens ◽  
...  
Keyword(s):  
Electrons And Ions

scholarly journals Charged particle guiding and beam splitting with auto-ponderomotive potentials on a chip

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Robert Zimmermann ◽  
Michael Seidling ◽  
Peter Hommelhoff
Keyword(s):  
Charged Particle ◽  
Large Range ◽  
Proof Of Concept ◽  
Beam Splitting ◽  
Particle Beams ◽  
Effective Potentials ◽  
Charged Particle Beams ◽  
Electrons And Ions ◽  
Ponderomotive Forces ◽  
Planar Substrates

AbstractElectron and ion beams are indispensable tools in numerous fields of science and technology, ranging from radiation therapy to microscopy and lithography. Advanced beam control facilitates new functionalities. Here, we report the guiding and splitting of charged particle beams using ponderomotive forces created by the motion of charged particles through electrostatic optics printed on planar substrates. Shape and strength of the potential can be locally tailored by the lithographically produced electrodes’ layout and the applied voltages, enabling the control of charged particle beams within precisely engineered effective potentials. We demonstrate guiding of electrons and ions for a large range of energies (from 20 to 5000 eV) and masses (from 5 · 10−4 to 131 atomic mass units) as well as electron beam splitting for energies up to the keV regime as a proof-of-concept for more complex beam manipulation.

scholarly journals Reply to ‘‘Comment on ‘Peeling of convection cells and the generation of sheared flow’ [Phys. Fluids B 4, 488 (1992)]’’

1993 ◽  
Vol 5 (2) ◽  
pp. 658-658
Author(s):  
J. F. Drake ◽  
J. M. Finn ◽  
P. N. Guzdar ◽  
V. Shapiro ◽  
V. Shevchenko ◽  
...  
Keyword(s):  
Sheared Flow
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