arXiv subjects

D. Pan

Publications and source records attributed to D. Pan.

4 recordsLinked to original sources

arXiv2026

Dual-pulse micronozzle acceleration of sub-GeV-class protons

We propose a dual-pulse micronozzle acceleration scheme that enables phase-locked acceleration of laser-driven protons, mitigating the trade-off between maximum proton energy and laser-to-proton conversion efficiency. A delay-tuned synchronization window injects a compact proton front generated by a shaping prepulse into a quasistatic axial electric field driven by a delayed main pulse in a micronozzle cavity. Phase locking preserves the relative phase between the proton bunch and the accelerating field, suppresses thermal debunching, and prolongs the acceleration stage. At main-pulse intensities of order 10^21 W/cm^2, sub-GeV proton cutoff energies are obtained with a total laser-to-proton conversion efficiency of about 20%. The efficiency for protons above 100 MeV exceeds about 13%, indicating preferential energy loading into a compact proton population. Simulations with an unconfined dual-pulse hydrogen rod show that the improvement results from temporal synchronization and geometric confinement, which sustain a long-lived axial accelerating channel. An analytical synchronization model agrees with the simulations. Three-dimensional particle-in-cell simulations confirm that phase locking and spectral hardening are preserved in slit-nozzle geometries, with cutoff energies about 60% higher than those of an unconfined hydrogen rod. These results establish phase-locked acceleration as a practical design principle for compact, high-yield sub-GeV proton drivers for secondary-particle applications.

physics.plasm-ph↗

arXiv2025

Gigagauss magnetic field generation by bladed microtube implosion

We demonstrate the generation of ultrahigh magnetic fields in the order of gigagauss using a bladed microtube target whose inner surface is periodically slanted in a sawtooth-like pattern. When irradiated by ultra-intense, ultrashort laser pulses, hot electrons with MeV energies are produced at the outer surface and swiftly transported to the inner surface, initiating a rapid implosion of plasma toward the central axis. The unique blade-induced asymmetry gives rise to vortex-shaped flows of ions and electrons near the center, forming strong azimuthal loop currents that generate ultrahigh magnetic fields at the center. Two-dimensional particle-in-cell simulations, supported by a simple analytical model, elucidate the underlying physics and reveal key scaling laws governing the field strength and spatial confinement.

physics.plasm-ph↗

arXiv2024

Giant interfacial Dzyaloshinskii-Moriya Interaction in perovskite La_{0.7}Sr_{0.3}MnO_{3} films

The Dzyaloshinskii-Moriya interaction (DMI) plays a critical role in stabilizing topological spin textures, a key area of growing interest in oxide-based spintronics. While most of reported topological phenomena found in manganites are related to the bulk-like DMI, the understanding of interfacial DMI and its origin in oxide interfaces remain limited. Here we experimentally investigate the interfacial DMI of La_{0.7}Sr_{0.3}MnO_{3} (LSMO) films grown on various substrates by employing spin-wave propagation with drift velocities at room temperature. Our findings reveal a giant interfacial DMI coefficient (\mathit{D} _{s}) of 1.96 pJ/m in LSMO/NdGaO_{3}(110) system, exceeding previously reported values in oxides by one to two orders of magnitude. First-principles calculations further show that with the aid of 6\mathit{s} electrons, the 4\mathit{f} electrons from Nd play a key role in enhancing the spin-orbit coupling of the 3\mathit{d} electrons in Mn, ultimately leading to the observed giant interfacial DMI. This discovery of giant interfacial DMI through engineering the interface of oxides provides valuable insights for advancing functional chiral magnonics and spintronics.

cond-mat.mtrl-sci↗

arXiv2013

Anomalous Hall Effect in Chemically Disordered L10-Mn1.5Ga

The anomalous Hall effect (AHE) in perpendicularly magnetized L10-Mn1.5Ga single-crystalline films is investigated as a function of degree of long-range chemical ordering and temperature. Our results provide firm evidence that phonons has negligibly smaller effect on skew scattering contributions to AHE resistivity than defects, the overlook of which in conventional scaling laws results in significant discrepancies and exponent n beyond 2 when fitting the data. We find that the broken of long-range chemical ordering strongly affects both intrinsic and extrinsic contributions of AHE conductivity, e.g., it greatly suppresses intrinsic contributions by influencing the topology of the band structures. Our results are of great importance for both physical understanding and technological engineering of the AHE.

cond-mat.mtrl-sci↗