ELFT HÍRADÓ

[Somogyi Gábor <somogyi.gabor AT wigner.hun-ren.hu>]

Wigner FK RMI Elméleti Osztály Szemináriuma
Tisztelettel meghívjuk


           Prof. Varró Sándor
           (ELI-ALPS Research Institute, Szeged)


"Mesoscopic radiation reaction in scattering of light by active boundary 
surfaces”


címmel tartandó szemináriumára.


Kivonat:



We shall discuss the dynamics of reflection and transmission of light pulses 
at active boundary surfaces, which are very thin conducting layers (metal, 
transient plasma, graphene) represented by current sheets (they may be 
embedded in dielectrics). The boundary conditions contain the unknown surface 
current components, whose electrons move under the action of the Lorentz 
force, which stems from the superposition of the incoming field and the 
unknown reflected and transmitted fields. This model gives a special closed 
set of coupled Maxwell-Lorentz equations, where a damping term automatically 
appears, as a result of a mesoscopic radiation reaction. The solutions of 
these equations allow us to predict several new effects, like the 
modification of the Fresnel coefficients, the appearance of frozen-in 
electromagnetic pulses [1], and the generation of rectangular optical waves 
[2]. The latter effect may perhaps be relevant for a physical realization of 
Haar wavelets [3] in the optical range. We shall also show our results on the 
time-dependent reflection and refraction of electromagnetic pulses on a 
system of two parallel current sheets [4]. Here the problem has been reduced 
to a hybrid system of two-delay differential equations for the electron 
motion in the layers and a recurrence relation for the scattered fields. The 
solution has been given as a limit of a singularly pertubed system. Finally, 
we plan to highlight some similarities of our analysis with the description 
of the classical radiation reaction problem concerning the early electron 
models [5].

References.

[1] Varró S : Linear and nonlinear absolute phase effects in interactions of 
ulrashort laser pulses with a metal nano-layer or with a thin plasma layer. 
Laser and Particle Beams 25, 379 (2007). E-print: arXiv: physics/0610266 
[physics.plasm-ph].

[2] Varró S; Graphene-based carrier-envelope phase difference meter. AIP  
Conf. Proceedings 1462, 128 (2012). [2a] Varró S, Generation of rectangular 
optical waves by relativistic clipping. Laser Physics 23, 056006 (2013). 
E-print: arXiv:1301.6103 [physics.optics].

[3] Haar A, Zur Theorie der orthogonalen Funktionensysteme (Inaugural 
Dissertation zur Erlangung der Doktorwürde der hohen philosophischen Fakultät 
der Georg-August-Universität zu Göttingen, vorgelegt von Alfred Haar aus 
Budapest). 1909, 1-49; [3a] Haar A, Mathematische Annalen 69, 331-371 (1910); 
[3b] Haar A, Mathematische Annalen 71, 38-53 (1911).

[4] Polner M, Varró S and Vörös‐Kiss A, The role of the time delay in the 
reflection and transmission of ultrashort electromagnetic pulses on a system 
of parallel current sheets. Physica Scripta 94, 045205 (2019). E-print: 
arXiv: 1812.03857v1 [physics.class-ph].

[5] Spohn H, The critical manifold of the Lorentz-Dirac equation. Europhys. 
Lett. 50, 287 (2000). [5a] Rohrlich F, The correct equation of motion of a 
classical point charge. Physics Letters A 283, 276-278 (2001). [5b] Yaghjian 
A D, Relativistic Dynamics of a Charged Sphere. Updating the Lorentz-Abraham 
Model, 2nd ed. Lect. Notes Phys. 686 (Springer, New York 2006).



Helye: Wigner FK RMI III. ép. Tanácsterem
Ideje: 2026 február 6. péntek d.u. 2 óra

Szívesen látunk minden érdeklődőt.


                      Somogyi Gábor