ELFT HÍRADÓ

[<vera.horvath AT eli-alps.hu>]

Előadó:    Varró Sándor (MTA Wigner Fizikai Kutatóközpont, ELI-ALPS)
Cím:          Klein-Gordon radio and laser acceleration of particles

Időpont:  2019. május 3., 10 óra
Helyszín: ELI-ALPS konferenciaterme; Szeged, Wolfgang Sandner utca 3.

Az előadás kivonata:
In the present talk,  first we show that the four potential of electromagnetic
fields in a plasma medium can be considered as a massive vector boson field,
where the mass is proportional with the plasma frequency. Similar vector
fields has long been known in quantum electrodynamics from the works of
Lánczos [1] and Proca [2], but these do not rely on plasma considerations. The
„mass-generation mechanism” has been described by Anderson [3] in solid state
physics, and the research in particle physics on this subject has recently
culminated in the detection of the Higgs particle [4].
The plane waves of the »Lánczos-Proca fields« have three orthogonal
polarizatons, whose amplitudes satisfy the Klein-Gordon equation. The
expression „Klein-Gordon radio” in the title of the present talk has been
borrowed from the paper by Crandall and Wheeler [5], devoted to the study of a
dynamical bound on photon mass. These authors presented the peculiarities of
wave propagation in free space, such as the appearance of wake-fields and the
special Doppler effect of radio signals from a rapidly receding massy-photon
transmitter. We show that similar phenomena are also relevant in the so-called
laser wake-field accelerators and in the generation of high harmonics (and
attosecond pulses) by relativistic electrons, interacting with extremely high
intensity laser fields in a plasma environment. On the basis of recently found
new exact solutions of the relativistic wave equations of charged particles
[6], we also show that very high contrast density modulations are generated,
serving as »quantum bubbles« to accelerate electrons [7]. In the last part of
the talk we consider exact analytic solutions of the relativistic equation of
motion of a point electron interacting with a high-intensity laser field in
vacuum [8] and in a plasma medium, and compare the particle dynamics (laser
acceleration) and the radiation properties (attosecond light pulse generation)
in these two cases.

References.
[1] Lánczos C, Die tensoranalytischen Beziehungen der Diracschen Gleichung. Z.
für Physik 57, 447 (1929).
[2] Proca A, Sur la théorie ondulatoire des électrons positifs et négatifs. J.
Phys. Radium 7, 347-353 (1936).
[3] Anderson P W, Plasmons, gauge invariance, and mass. Phys. Rev. 130, 439-
442 (1963).
[4] Higgs P W, Evading the Goldstone theorem. Ann. Phys. (Berlin) 526, 211-213
(2014). [Nobel Lecture, 8 December 2013.]
[5] Crandall R E, Wheeler N A, Klein-Gordon radio and the problem of photon
mass. Nuovo Cim. 80B, 231-242 (1984).
[6] Varró S, New exact solutions of the Klein-Gordon and Dirac equations of a
charged particle propagating in a strong laser field in an underdense plasma.
Nucl. Instr. and Methods in Phys. Research A  740, 280-283 (2014).
[7] Varró S, Quantum description of relativistic charged particles interacting
with a strong laser field in a plasma, represented by Lanczos-Proca vector
bosons. Talk presented at EUCALL Joint Foresight Topical Workshop: Theory and
Simulation of Photon-Matter Interactions [ELI-ALPS, 1-6 July 2018, Szeged,
Hungary].
[8] Hack Sz, Varró S and Czirják A, Carrier-envelope phase controlled isolated
attosecond pulses in the nm wavelength range, based on coherent nonlinear
Thomson backscattering. New J. Phys. 20, 073043 (2018).

A szeminárium angol nyelvű. Minden érdeklődőt szívesen látunk.