THE TOWNSEND DISCHARGE IN A COAXIAL DIODE WITH AXIAL MAGNETIC FIELD

1958 ◽  
Vol 36 (3) ◽  
pp. 255-270 ◽  
Author(s):  
P. A. Redhead
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Space Charge ◽  
Transit Time ◽  
Pressure Range ◽  
Axial Magnetic Field ◽  
Constant Electric Field ◽  
Approximate Theory ◽  
Charge Effects ◽  
Townsend Discharge

An approximate theory is developed of the breakdown characteristics of a coaxial diode in an axial magnetic field, taking into account the effects of elastic collisions. It is assumed that the electron moves in a constant electric field between collisions and thus the theory is valid only in the appropriate range of magnetic field and voltage. Estimates of transit time and of space-charge effects are also made. Measurements in the pressure range 10−3 to 10−9 mm. Hg are in general agreement with the theory.

scholarly journals Statistical Study on Space Charge effects and Stage Characteristics of Needle-Plate Corona Discharge under DC Voltage

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2732 ◽  
Author(s):  
Disheng Wang ◽  
Lin Du ◽  
Chenguo Yao
Keyword(s):  
Electric Field ◽  
Space Charge ◽  
Corona Discharge ◽  
Discharge Process ◽  
Space Charge Effects ◽  
Discharge Characteristics ◽  
Charge Effects ◽  
Dc Voltage ◽  
Field Distributions ◽  
Space Charges

The air’s partial discharges (PD) under DC voltage are obviously affected by space charges. Discharge pulse parameters have statistical regularity, which can be applied to analyze the space charge effects and discharge characteristics during the discharge process. Paper studies air corona discharge under DC voltage with needle-plate model. Statistical rules of repetition rate (n), amplitude (V) and interval time (∆t) are extracted, and corresponding space charge effects and electric field distributions in PD process are analyzed. The discharge stages of corona discharge under DC voltage are divided. Furthermore, reflected space charge effects, electric field distributions and discharge characteristics of each stages are summarized to better explain the stage discharge mechanism. This research verifies that microcosmic process of PD under DC voltage can be described based on statistical method. It contributes to the microcosmic illustration of gas PD with space charges.

Space‐charge‐neutralized proton beam transport in an axial magnetic field

1990 ◽  
Vol 67 (2) ◽  
pp. 611-616 ◽  
Author(s):  
G. S. Kerslick ◽  
Cz. Golkowski ◽  
J. A. Nation ◽  
I. S. Roth ◽  
J. D. Ivers
Keyword(s):  
Magnetic Field ◽  
Space Charge ◽  
Proton Beam ◽  
Axial Magnetic Field ◽  
Beam Transport

scholarly journals Space Charge Fields in the Development of a Townsend Discharge in Nitrogen

1969 ◽  
Vol 22 (4) ◽  
pp. 447 ◽  
Author(s):  
AA Doran
Keyword(s):  
Light Intensity ◽  
Electric Field ◽  
Space Charge ◽  
Applied Electric Field ◽  
Dominant Role ◽  
Light Output ◽  
Exact Relation ◽  
Townsend Discharge ◽  
Discharge Gap ◽  
Infor Mation

As the CUlTent through a spark rises into the milliampere range, ionization due to fields produced by space charge plays an increasingly dominant role. Infor� mation on these fields can be obtained from analysis of the light intensity emitted at different points along the axis of the discharge. In an earlier publication (Doran 1968) photomultiplier records of the light output obtained at various times during the growth of a Townsend discharge in nitrogen (pd = 600 torr cm) were analysed by an approximate method. In the present paper a more exact relation between the light emitted and the variation in local electric field is derived, enabling the previous results to be re.analysed. This has provided a quantitative picture, spatially and temporally resolved, of the development of these fields, which are associated with luminous fronts observed to propagate back and forth across the discharge gap. The magnitude of the field variations is in general about 10-20% of the applied electric field.

scholarly journals Ion energy increase in laser-generated plasma expanding through axial magnetic field trap

2007 ◽  
Vol 25 (3) ◽  
pp. 453-464 ◽  
Author(s):  
L. Torrisi ◽  
D. Margarone ◽  
S. Gammino ◽  
L. Andò
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electric Fields ◽  
Axial Magnetic Field ◽  
Ion Beam ◽  
High Vacuum ◽  
Target Surface ◽  
Axial Direction ◽  
Ion Interactions ◽  
The Magnetic Field

Laser-generated plasma is obtained in high vacuum (10−7 mbar) by irradiation of metallic targets (Al, Cu, Ta) with laser beam with intensities of the order of 1010 W/cm2. An Nd:Yag laser operating at 1064 nm wavelength, 9 ns pulse width, and 500 mJ maximum pulse energy is used. Time of flight measurements of ion emission along the direction normal to the target surface were performed with an ion collector. Measurements with and without a 0.1 Tesla magnetic field, directed along the normal to the target surface, have been taken for different target-detector distances and for increasing laser pulse intensity. Results have demonstrated that the magnetic field configuration creates an electron trap in front of the target surface along the axial direction. Electric fields inside the trap induce ion acceleration; the presence of electron bundles not only focuses the ion beam but also increases its energy, mean charge state and current. The explanation of this phenomenon can be found in the electric field modification inside the non-equilibrium plasma because of an electron bunching that increases the number of electron-ion interactions. The magnetic field, in fact, modifies the electric field due to the charge separation between the clouds of fast electrons, many of which remain trapped in the magnetic hole, and slow ions, ejected from the ablated target; moreover it increases the number of electron-ion interactions producing higher charge states.

Basic features of a charged particle dynamics in a laser beam with static axial magnetic field

2009 ◽  
Vol 17 (4) ◽  
Author(s):  
A. Dubik ◽  
M.J. Małachowski
Keyword(s):  
Magnetic Field ◽  
Charged Particle ◽  
Kinetic Energy ◽  
Electric Field ◽  
Laser Beam ◽  
Analytical Solutions ◽  
Axial Magnetic Field ◽  
Dynamic Equations ◽  
Graphical Form ◽  
Particle Rotation

AbstractIn this paper, the trajectory and kinetic energy of a charged particle, subjected to interaction from a laser beam containing an additionally applied external static axial magnetic field, have been analyzed. We give the rigorous analytical solutions of the dynamic equations. The obtained analytical solutions have been verified by performing calculations using the derived solutions and the well known Runge-Kutta procedure for solving original dynamic equations. Both methods gave the same results. The simulation results have been obtained and presented in graphical form using the derived solutions. Apart from the laser beam, we show the results for a maser beam. The obtained analytical solutions enabled us to perform a quantitative illustration, in a graphical form of the impact of many parameters on the shape, dimensions and the motion direction along a trajectory. The kinetic energy of electrons has also been studied and the energy oscillations in time with a period equal to the one of a particle rotation have been found. We show the appearance of, so-called, stationary trajectories (hypocycloid or epicycloid) which are the projections of the real trajectory onto the (x, y) plane. Increase in laser or maser beam intensity results in the increase in particle’s trajectory dimension which was found to be proportional to the amplitude of the electric field of the electromagnetic wave. However, external magnetic field increases the results in shrinking of the trajectories. Performed studies show that not only amplitude of the electric field but also the static axial magnetic field plays a crucial role in the acceleration process of a charged particle.At the authors of this paper best knowledge, the precise analytical solutions and theoretical analysis of the trajectories and energy gains by the charged particles accelerated in the laser beam and magnetic field are lacking in up to date publications. The authors have an intention to clarify partly some important aspects connected with this process. The presented theoretical studies apply for arbitrary charged particle and the attached figures-for electrons only.

Stability of a positive column in the presence of an axial magnetic field

1982 ◽  
Vol 28 (1) ◽  
pp. 113-124 ◽  
Author(s):  
Mahinder S. Uberoi ◽  
Chuen-Yen Chow
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electron Density ◽  
Electric Fields ◽  
Positive Column ◽  
Axial Magnetic Field ◽  
Previous Analysis ◽  
Self Consistent ◽  
The Stability ◽  
Axisymmetric Perturbations

Self-consistent infinitesimal perturbations of electron density and electric field are used to analyse the stability of the plasma. The axisymmetric perturbations are stable for any magnetic and electric field strengths. The non-axisymmetric perturbations with azimuthal modes m ≥ 1 and less than a certain integer are unstable for certain ranges of magnetic and electric fields. The mode m = 2 can be more unstable than the mode m = 1. Previous analysis by other authors was confined to the case m = 1 and the perturbations were not self-consistent. Our results differ significantly from the earlier results.

Sign in / Sign up

Export Citation Format

Share Document