185 research outputs found
Dependence of volume FEL (VFEL) threshold conditions on undulator parameters
The idea and principles of volume free electron lasers were proposed in
[1-4]. It was shown there that volume distributed feedback (VDFB) can
essentially reduce the threshold current of generation and provide the
possibility of smooth frequency tuning. The present work considers an undulator
VFEL with multiwave VDFB. It is shown that dependence of threshold current on
the interaction length changes in the point of roots degeneration. This leads
to the sharp decrease of start current if condition of dynamical diffraction is
fulfilled. The dependence of amplification coefficient changes, too. So the
interaction length for generation appears shorter. The proposed scheme can be
used for generation in wide spectral range from microwaves to X-rays. The
operating features of undulator VFEL is considered.Comment: Latex, 6 pages with 2 Postscript figure
Formation of singularities on the surface of a liquid metal in a strong electric field
The nonlinear dynamics of the free surface of an ideal conducting liquid in a
strong external electric field is studied. It is establish that the equations
of motion for such a liquid can be solved in the approximation in which the
surface deviates from a plane by small angles. This makes it possible to show
that on an initially smooth surface for almost any initial conditions points
with an infinite curvature corresponding to branch points of the root type can
form in a finite time.Comment: 14 page
Nonstationary stage of quasi‐cherenkov beam instability in periodical structures
Analysis of nonstationary stage of quasi‐Cherenkov instability of electron beam in the case of two‐wave distributed feedback is carried out. Mathematical models and numerical methods of nonstationary quasi‐Cherenkov electron beam instability are proposed. Results of numerical experiments are proposed. Bifurcations of nonstationary solution are discussed.
Straipsnyje analizuojama nestacionariosios fazes kvazi‐Cherenkovo elektronu spinduliuotes nestabilumas esant dvieju bangu saveikai su grižtamo ryšio pernešimu. Pasiūlyti šios elektronu spinduliuotes nestacionariosios fazes atveju matematiniai ir skaitiniai sprendimo metodai. Pateikti skaitinio eksperimento rezultatai. Aptartos nestacionariojo sprendinio bifurkacijos.
First Published Online: 14 Oct 201
- …