Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Yanjun Gu is active.

Publication


Featured researches published by Yanjun Gu.


Physical Review E | 2016

Fast magnetic-field annihilation in the relativistic collisionless regime driven by two ultrashort high-intensity laser pulses.

Yanjun Gu; O. Klimo; Deepak Kumar; Yue Liu; Sushil Kumar Singh; T. Zh. Esirkepov; S. V. Bulanov; S. Weber; G. Korn

The magnetic quadrupole structure formation during the interaction of two ultrashort high power laser pulses with a collisionless plasma is demonstrated with 2.5-dimensional particle-in-cell simulations. The subsequent expansion of the quadrupole is accompanied by magnetic-field annihilation in the ultrarelativistic regime, when the magnetic field cannot be sustained by the plasma current. This results in a dominant contribution of the displacement current exciting a strong large scale electric field. This field leads to the conversion of magnetic energy into kinetic energy of accelerated electrons inside the thin current sheet.


Physics of Plasmas | 2015

Fast magnetic field annihilation driven by two laser pulses in underdense plasma

Yanjun Gu; O. Klimo; Deepak Kumar; S. V. Bulanov; T. Zh. Esirkepov; S. Weber; G. Korn

Fast magnetic annihilation is investigated by using 2.5-dimensional particle-in-cell simulations of two parallel ultra-short petawatt laser pulses co-propagating in underdense plasma. The magnetic field generated by the laser pulses annihilates in a current sheet formed between the pulses. Magnetic field energy is converted to an inductive longitudinal electric field, which efficiently accelerates the electrons of the current sheet. This new regime of collisionless relativistic magnetic field annihilation with a timescale of tens of femtoseconds can be extended to near-critical and overdense plasma with the ultra-high intensity femtosecond laser pulses.


Physics of Plasmas | 2016

Explosion of relativistic electron vortices in laser plasmas

K. V. Lezhnin; F. F. Kamenets; T. Zh. Esirkepov; S. V. Bulanov; Yanjun Gu; S. Weber; G. Korn

The interaction of high intensity laser radiation with underdense plasma may lead to the formation of electron vortices. Though being quasistationary on an electron timescales, these structures tend to expand on a proton timescale due to Coloumb repulsion of ions. Using a simple analytical model of a stationary vortex as initial condition, 2D PIC simulations are performed. A number of effects are observed such as vortex boundary field intensification, multistream instabilities at the vortex boundary, and bending of the vortex boundary with the subsequent transformation into smaller electron vortices.


Proceedings of SPIE | 2015

Evolution of relativistic solitons in underdense plasmas

Yue Liu; Ondrej Klimo; Yanjun Gu; Deepak Kumar; Sushil Singh; Sergei V. Bulanov; Timur Zh. Esirkepov; S. Weber; Georg Korn

Relativistic solitons arising from the interaction of an intense laser pulse with underdense plasmas are investigated. We show the formation and evolution of the relativistic solitons in a collisionless cold plasma with two dimensional particle-in-cell simulations. Such a kind of solitons will evolve into postsolitons if the time scale is longer than the ion response time. Generally, a substantial part of the pulse energy is transformed into solitons during the soliton formation. This fairly high efficiency of electromagnetic energy transformation can play an important role in the interaction between the laser pulse and the plasma. The energy exchange between the electromagnetic field and the kinetic energy of the soliton is discussed. In homogeneous plasmas, the solitons tend to stay close to the region where they are generated and dissipate due to the interaction with surrounding particles eventually. While the laser pulse propagates through inhomogeneous plasmas, the solitons are accelerated along the plasma density gradient towards lower density.


Proceedings of SPIE | 2015

Magnetic reconnection research with petawatt-class lasers

Yanjun Gu; Ondrej Klimo; Deepak Kumar; Yue Liu; Sushil Kumar Singh; Sergei V. Bulanov; Timur Zh. Esirkepov; Stefan Weber; G. Korn

Magnetic reconnection is regarded as a fundamental phenomenon in space and laboratory plasmas. It converts magnetic energy to kinetic energy of plasma particles through the topological rearrangements of the magnetic field lines. Magnetic reconnection is believed to play an important role in the solar systems, such as solar flares and coronal mass ejections. Observations of rapid energy release in solar flare and the global convection pattern within the magnetosphere are strongly suggestive that reconnection must be occurring. With the development of laser technology, high power laser facilities have made great progress in recent decades. Ultra powerful pulse with TW and PW are available now. As a result, the laser-matter interaction enters regimes of interest for laboratory astrophysics such as magnetic reconnection. J. Y. Zhong et al.1 reported an experiment about Xray source emission by reconnection outflows. Two intense lasers with long pulse duration are focused on the solid Aluminum target to generate hot electrons. In this paper, we employ a hydrogen foam target with near critical density to investigate the reconnection. Two parallel ultra intense pulses are injected into the target. By the effect of laser wakefield acceleration, two strong electron beam are generated and both of them induce a magnetic dipole structure. With the expansion of the dipole, magnetic field annihilation occurs in the center part of the target. The induced electric field and particle acceleration are detected in the simulations as evidence for magnetic reconnection. The effects of separation distance between two laser pulses and laser intensity on magnetic reconnection are also discussed.


Physics of Plasmas | 2015

Evolution of laser induced electromagnetic postsolitons in multi-species plasma

Yue Liu; O. Klimo; Timur Zh. Esirkepov; Sergei V. Bulanov; Yanjun Gu; S. Weber; G. Korn

The evolution of an s-polarized relativistic electromagnetic soliton created in multi-species plasma by an intense short laser pulse is investigated using two-dimensional particle-in-cell simulations. The multi-component plasma consists of electrons and high-Z ions with a small addition of protons. By comparison, the evolution of postsoliton is very different from that in hydrogen plasma. A halo-like structure is found in spatial patterns of both electromagnetic fields and electron densities. The process of energy depletion is much slower due to the smaller charge-to-mass ratio of ions, which implies a better way of detecting postsolitons in simulations and experiments. In addition, it is found that the Coulomb explosion of high-Z ions in the postsoliton stage facilitates low-Z ion acceleration, and the maximum energy of low-Z ions increases with the component ratio of high-Z to low-Z ions.


High Power Laser Science and Engineering | 2016

Fast magnetic energy dissipation in relativistic plasma induced by high order laser modes

Yanjun Gu; Q. Yu; O. Klimo; T. Zh. Esirkepov; S. V. Bulanov; S. Weber; G. Korn


Plasma Physics and Controlled Fusion | 2018

Splitter target for controlling magnetic reconnection in relativistic laser plasma interactions

Yanjun Gu; Stepan Bulanov; G. Korn; Sergei V. Bulanov


Optics Express | 2018

Intense, directional and tunable γ-ray emission via relativistic oscillating plasma mirror

Yanjun Gu; Stefan Weber


Applied Sciences | 2018

HELL: High-Energy Electrons by Laser Light, a User-Oriented Experimental Platform at ELI Beamlines

T. Levato; Stefano Bonora; Gabriele Maria Grittani; Carlo Maria Lazzarini; Muhammad Nawaz; Michal Nevrkla; Leonardo Villanova; Roberto Ziano; Silvano Bassanese; N. A. Bobrova; Katia Casarin; Edwin Chacon-Golcher; Yanjun Gu; Danila Khikhlukha; D. Kramer; Marco Lonza; D. Margarone; Veronika Olšovcová; Marcin Rosinski; Bedrich Rus; Pavel V. Sasorov; Roberto Versaci; Agnieska Zaraś-Szydłowska; Sergei V. Bulanov; G. Korn

Collaboration


Dive into the Yanjun Gu's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar

Sergei V. Bulanov

Japan Atomic Energy Agency

View shared research outputs
Top Co-Authors

Avatar

O. Klimo

Czech Technical University in Prague

View shared research outputs
Top Co-Authors

Avatar

Deepak Kumar

Jawaharlal Nehru University

View shared research outputs
Top Co-Authors

Avatar

Yue Liu

Shanghai Jiao Tong University

View shared research outputs
Top Co-Authors

Avatar

S. V. Bulanov

Japan Atomic Energy Agency

View shared research outputs
Top Co-Authors

Avatar

T. Zh. Esirkepov

Japan Atomic Energy Agency

View shared research outputs
Top Co-Authors

Avatar

Ondrej Klimo

Czech Technical University in Prague

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge