IPAC2015 - List of Authors (Rizzato, F.B.)

Paper	Title	Page
MOPWA002	Nonequilibrium Phase Transitions in Crossed-Field Devices	74
	S. Marini, R. Pakter, F.B. Rizzato IF-UFRGS, Porto Alegre, Brazil
	Funding: This work was partially supported by CNPq and FAPERGS, Brazil, and by the US-AFOSR under the grant FA9550-09-1-0283. This work presents a fully kinetic description to model the electron flow in the electronic crossed-field configuration observed in a smooth-bore magnetron. Through this model, it has been observed that, according to the electromagnetic field, the injection temperature and the charge density, the electron flow can be classified in two different stationary modes: magnetic insulation mode where most of the electrons returning to the cathode after a transient time and Child-Langmuir mode where most of the electrons reach the anode after a transient time. Focusing on magnetic insulated mode, it has been found that charge density and injection temperature define whether electrons are accelerated (accelerating regime) or decelerated (space-charge limited regime) on the cathode. Besides, when the injection temperature is relatively low (high), a small charge increase causes (does not cause) an abrupt transition between accelerating and space-charge limited regime. Basing on the results, it was possible to identify a critical temperature that separates abrupt and continuous behavior. The results have been verified by using self-consistent computer simulations. S. Marini, F. B. Rizzato, and R. Pakter, Phys. Plasmas 21, 083111 (2014).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA002
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TUPWA008	Mixing and Space-Charge Effects In Free-Electron Lasers	1410
	E.A. Peter, A. Endler, F.B. Rizzato IF-UFRGS, Porto Alegre, Brazil A.P.B. Serbeto UFF, Niterói - RJ, Brazil
	Funding: This work was supported by CNPq and FAPERGS, Brazil, and by the Air Force Office of Scientific Research (AFOSR), USA, under the Grant No. FA9550-12-1-0438 Free-electron lasers are devices which efficiently convert the kinetic energy from a relativistic electron beam into electromagnetic radiation, amplifying an initial small sign. The present work revisits the subject of mixing, saturation and space-charge effects in free-electron lasers. Use is made of the compressibility factor, which proves to be a helpful tool in the related systems of charged beams confined by static magnetic fields. The compressibility allows to build a semi-analytical model and to perform analytical estimates of the elapsed time until the onset of mixing, which in turn allows to estimate the saturated amplitude of the radiation field. In addition, the compressibility helps to pinpoint space-charge effects and the corresponding transition from Compton to Raman regimes. The semi-analytical model and the particles simulations are compared, exhibiting a good agreement.* * E. Peter, A. Endler, F. B. Rizzato, and A. Serbeto, Phys. Plasmas 20, 123104 (2013). ** E. Peter, A. Endler, and F. B. Rizzato, Phys. Plasmas 21, 113104 (2014)
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA008
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Paper

Title

Page

Nonequilibrium Phase Transitions in Crossed-Field Devices

74

S. Marini, R. Pakter, F.B. Rizzato
IF-UFRGS, Porto Alegre, Brazil

Funding: This work was partially supported by CNPq and FAPERGS, Brazil, and by the US-AFOSR under the grant FA9550-09-1-0283.
This work presents a fully kinetic description to model the electron flow in the electronic crossed-field configuration observed in a smooth-bore magnetron. Through this model, it has been observed that, according to the electromagnetic field, the injection temperature and the charge density, the electron flow can be classified in two different stationary modes: magnetic insulation mode where most of the electrons returning to the cathode after a transient time and Child-Langmuir mode where most of the electrons reach the anode after a transient time. Focusing on magnetic insulated mode, it has been found that charge density and injection temperature define whether electrons are accelerated (accelerating regime) or decelerated (space-charge limited regime) on the cathode. Besides, when the injection temperature is relatively low (high), a small charge increase causes (does not cause) an abrupt transition between accelerating and space-charge limited regime. Basing on the results, it was possible to identify a critical temperature that separates abrupt and continuous behavior. The results have been verified by using self-consistent computer simulations*.
*S. Marini, F. B. Rizzato, and R. Pakter, Phys. Plasmas 21, 083111 (2014).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPWA008

Mixing and Space-Charge Effects In Free-Electron Lasers

1410

E.A. Peter, A. Endler, F.B. Rizzato
IF-UFRGS, Porto Alegre, Brazil
A.P.B. Serbeto
UFF, Niterói - RJ, Brazil

Funding: This work was supported by CNPq and FAPERGS, Brazil, and by the Air Force Office of Scientific Research (AFOSR), USA, under the Grant No. FA9550-12-1-0438
Free-electron lasers are devices which efficiently convert the kinetic energy from a relativistic electron beam into electromagnetic radiation, amplifying an initial small sign. The present work revisits the subject of mixing, saturation and space-charge effects in free-electron lasers. Use is made of the compressibility factor, which proves to be a helpful tool in the related systems of charged beams confined by static magnetic fields. The compressibility allows to build a semi-analytical model and to perform analytical estimates of the elapsed time until the onset of mixing, which in turn allows to estimate the saturated amplitude of the radiation field. In addition, the compressibility helps to pinpoint space-charge effects and the corresponding transition from Compton to Raman regimes. The semi-analytical model and the particles simulations are compared, exhibiting a good agreement.*
* E. Peter, A. Endler, F. B. Rizzato, and A. Serbeto, Phys. Plasmas 20,
123104 (2013).
** E. Peter, A. Endler, and F. B. Rizzato, Phys. Plasmas 21, 113104 (2014)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA008

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)