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Radially polarized (RP) Hermite-Cosh-Gaussian (HChG) laser beam has been employed to study electron acceleration in an ion channel. As RP-HChG laser beam focus earlier, depending on this property electron acquires high order energy over short periods of time. The ion channel generates an electric field that prevents electrons from escaping from the interaction zone and maintains betatron resonance. Electron's energy gain has been analyzed by varying different parameters like: intensity parameter ( a 0 ), laser spot size ( r 0 ), decentered parameter (b ), ion density ( n i ). The combined effect of RP-HChG laser beam and ion channel causes an efficient energy enhancement of electron in the order of GeV. RP-HChG beam is a unique kind of laser beam, combining the characteristics of both Hermite Gaussian and hyperbolic cosine Gaussian modes. It can be tightly focused to produce a small spot with a high-intensity region at the focal point. The schematic depicts the electron acceleration by Radially Polarised Hermite Cosh Gaussian laser beam in a Plasma Ion Channel. Due to the early focusing effect of the HChG laser beam, it is remarkably better suitable than other laser beams for gaining GeV order energy over short time period. The coordination between better trapping laser light (RP) and electrostatic field of ion density channel encloses the electron to traverse a considerable distance and attains higher energy along longitudinal direction. It is clearly noticed that HChG laser beam is very much sensitive in ion channel. [ABSTRACT FROM AUTHOR]

Comparative study of electron acceleration by linearly polarized (LP) and circularly polarized (CP) Hermite-cosh-Gaussian lasers in vacuum has been analyzed. Hermite-cosh-Gaussian profile is a special kind of Gaussian profile whose decentered parameter (b) plays a crucial role in the electron acceleration. It has been observed that the electron energy enhancement for CP laser pulse is much higher as compared to LP laser pulse for optimized values of laser parameters like laser intensity parameter (a0), laser spot size (r0), etc. It is seen from the results that maximum electron energy gain increases rapidly with the increase in the value of decentred parameter for CP laser. The electron enhances more rapidly with propagation distance z for CP laser pulse. This energy enhancement persists continuously for the successive increment of the laser spot size (r0) and b. The laser mode index is also responsible for the electron energy enhancement. The plotted graphs also reveal that the energy enhancement is higher for CP laser pulse as compared to LP laser pulse for different parameters. [ABSTRACT FROM AUTHOR]

Electron acceleration due to the beating of two linearly polarized lasers of finite spot size at an arbitrary angle in a vacuum has been investigated. The interference at certain angles due to these lasers with slightly different frequencies interacting at any arbitrary angle has been studied. Due to the constructive interference between these lasers, their resultant electric and magnetic field points out in a particular direction, where the electron is injected for effective trapping and noticeable acceleration has been observed. Sensitiveness of chirp parameters on electron acceleration have been observed. Along with this, a periodic frequency chirp plays a crucial role in the improved acceleration of electron. In this way, electron energy is enhanced more conveniently. [ABSTRACT FROM AUTHOR]

Singly and multiply charged molecular ions are found in diverse environments and hold relevance for a wide range of research areas like combustion chemistry, accelerator physics, atmospheric sciences, plasma physics, astrophysics etc. Molecular dications are of special significance as they can be generated and studied comparatively easily in laboratory experiments. And they have enabled exploration of new and exciting phenomenon such as hydrogen migration, inter-atomic Coulombic decay, plasmonic excitations, orbital tomography etc. The lifetime of a molecular dication is one of its fundamental characteristics, whose measurement contributes to strengthening ab initio calculations and in predicting the concentration of its dissociation products. Most of the already reported lifetimes of molecular dications are in the range of nanoseconds to seconds and metastable states with lifetimes of the order of picoseconds have only been theoretical predicted and an experimental verification is pending. We present a method of measuring subrotational lifetimes of molecular dications formed in three-body sequential breakup of polyatomic molecular precursors. Specifically, we have measured the subrotational lifetime of SO 2 + , which is formed as an intermediate in the three-body sequential fragmentation of SO 2 3 + . The lifetime against dissociation is determined to be a fraction of the rotational period of SO 2 + and is of the order of few picoseconds. The method proposed is general and is not restricted to triatomic precursors. [ABSTRACT FROM AUTHOR]

The paper presents a scheme of vacuum electron acceleration due to tightly focused linearly polarized (LP) frequency chirped laser in the presence external magnetic field. The focused terawatt chirped laser pulse and the external axial magnetic field enable the electron of few MeV initial energy to attain high energy in GeV range, hence, explore the possibility of efficient electron acceleration. This can be achieved by optimizing the focused terawatt chirped laser and axial magnetic field parameters for resonance, which is realized between the electron and electric field of the tightly focused laser pulse. The frequency chirp plays a crucial role in enforcing resonance condition for longer duration and the applied magnetic field strongly enforces the electron to remain in the accelerating phase, thereby, both factors are equally imperative for accomplishing high electron energy gain in GeV. The presence of optimum axial magnetic field (~8.5 MG) along with optimum value of linear frequency chirp for laser intensity 1.38 × 1020 W/cm2 results in electron beam with energy ~5.78 GeV. During acceleration process, electron energy gain is highly sensitive to the initial phase of laser along with the frequency chirp and magnetic field. Electron trajectories in the influence of frequency chirp and magnetic field are also analyzed. [ABSTRACT FROM AUTHOR]

Retraction Note to: Optical and Quantum Electronics (2022) 54:684 https://doi.org/10.1007/s11082-022-04091-y The publisher has retracted this article and removed its contents because it was published due to an administrative error. Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. [Extracted from the article]