## Influence of inhomogeneous electric field geometry factors on runaway electrons generation conditions

Yuriy Mamontov, N.S. Semeniuk, N.M. Zubarev, I.V. Uimanov

Institute of Electrphysics UB RAS, 106, Amundsena st., 620016, Yekaterinburg, Russian Federation

VS

Valery Shklyaev
2020-09-17 12:10

Clarify, please, do you ignore the effect of the space charge on the electric field?

Are you considering a model with a constant electric field over time?

I don't understand why slide 12 shows the current and the spectrum in one picture. :)

YM

*Author*

Yuriy Mamontov
2020-09-17 12:18

Valery Shklyaev 2020-09-16 15:57

Clarify, please, do you ignore the effect of the space charge on the electric field? Are you considering a model with a constant electric field over time? I don't understand why slide 12 shows the current and the spectrum in

The model applied is not self-consistent, so a space charge is not taken into account. Actually, similarly to an analytic model, both models (the Monte-Carlo and the kinetic model) investigate electron energy balance in a space-inhomogeneous electric field, but this field is considered to be constant in time. The aim of the work is to collect statistics on running away of electrons in such a field without consideration of a space charge effect. Such an approach is valid because of two aspects. First, it's a well-known fact, that a RE beam during its propagation toward an anode advances an ionization wave, so, in the first approximation, we can assume that the RE beam moves in a non-distorted field. Second, in our work we look for threshold values of a voltage and an electric field strength. Near the threshold, a number of REs is small, contribution of REs in an ionization process is relatively small too, so, in terms of threshold values, a space charge can be neglected. It is so-called "a single-electron approximation".

A current and spectrum of electrons at an anode are given together, firstly, for the sake of minimization of plots and, secondly, to give an opportunity to compare the width of the RE current pulse and of the energy spectrum at the same time. It seems to be a suitable format for those plots presenting.

VS

Valery Shklyaev
2020-09-18 15:15

Yuriy Mamontov 2020-09-17 12:18

A current and spectrum of electrons at an anode are given together, firstly, for the sake of minimization of plots and, secondly, to give an opportunity to compare the width of the RE current pulse and of the energy spectrum at the same time. It seems to be a suitable format for those plots presenting.

I disagree with that. I think that currents on one graph and spectra on another are more convenient.

AK

Andrey Kozyrev
2020-09-23 18:30

Yuri, good report. There is one question. Slide 13 shows the right picture. Why does the number of electrons on all curves tend to the same value, 4*10^5?

YM

*Author*

Yuriy Mamontov
2020-09-23 18:30

Andrey Kozyrev 2020-09-23 14:57

Yuri, good report. There is one question. Slide 13 shows the right picture. Why does the number of electrons on all curves tend to the same value, 4*10^5?

In fact, it was an usual amount of simulated electrons. This value may be any other number, just in my numerical experiments I simulated 400 000 electrons, because It seemed to me it's an optimal value for the best agreement between accuracy and computational time on my workstation (a notebook with a 4-cores CPU). I agree, that it would be better if I gave this plots in relative units, not in an absolute number of runaway electrons :)

AK

Andrey Kozyrev
2020-09-24 13:14

Yuriy Mamontov 2020-09-23 18:30

In fact, it was an usual amount of simulated electrons. This value may be any other number, just in my numerical experiments I simulated 400 000 electrons, because It seemed to me it's an optimal value for the best

Thanks, Yuriy.