Efficient Particle Acceleration Research Articles

Probing the Low-velocity Regime of Nonradiative Shocks with Neutron Star Bow Shocks

Nonradiative shocks accelerate particles and heat astrophysical plasmas. While supernova remnants are the most well-studied example, neutron star (NS) bow shocks are also nonradiative and Balmer dominated. NS bow shocks are likely ubiquitous in the interstellar medium due to their large speeds imparted at birth, and they are thought to be a discrete source population contributing to the Galactic cosmic-ray spectrum. To date, nine NS bow shocks have been directly observed in Hα images. Most of these shocks have been characterized using narrowband Hα imaging and slit spectroscopy, which do not resolve the multicomponent velocity structure of the shocks and their spatial geometry. Here we present integral field spectroscopy of three NS bow shocks: J0742−2822, J1741−2054, and J2225+6535 (the Guitar Nebula). We measure the shock properties simultaneously in four dimensions: the 2D projected shock morphology, the radial velocity structure, and the Hα flux. The broad-to-narrow line ratio (I b/I n) is inferred from radial velocity profiles, and for J1741−2054, the narrow line is detected in multiple regions of the shock. The inferred line ratios and widths suggest that NS bow shocks represent a low-shock velocity regime (V ≲ 200 km s−1) in which I b/I n is high, distinct from the shock regime probed by supernova remnants. Our results illustrate a need for nonradiative shock models at velocities lower than previously considered, which will reveal the electron–ion temperature ratios and particle acceleration efficiencies of these bow shocks.

Probing Magnetic Fields in Young Supernova Remnants with IXPE

Synchrotron emission from the shocked regions in supernova remnants provides, through its polarization, crucial details about the magnetic field strength and orientation in these regions. This, in turn, provides information on particle acceleration in these shocks. Due to the rapid losses of the highest-energy relativistic electrons, X-ray polarization measurements allow for investigations of the magnetic field to be carried outvery close to the sites of particle acceleration. Measurements of both the geometry of the field and the levels of turbulence implied by the observed polarization degree thus provide unique insights into the conditions leading to efficient particle acceleration in fast shocks. The Imaging X-ray Polarimetry Explorer (IXPE) has carried out observations of multiple young SNRs, including Cas A, Tycho, SN 1006, and RX J1713.7−3946. In each, significant X-ray polarization detections provide measurements of magnetic field properties that show some common behavior but also considerable differences between these SNRs. Here, we provide a summary of results from IXPE studies of young SNRs, providing comparisons between the observed polarization and the physical properties of the remnants and their environments.

Discovery of Limb Brightening in the Parsec-scale Jet of NGC 315 through Global Very Long Baseline Interferometry Observations and Its Implications for Jet Models

We report the first observation of the nearby giant radio galaxy NGC 315 using a global very long baseline interferometry (VLBI) array consisting of 22 radio antennas located across five continents, including high-sensitivity stations, at 22 GHz. Utilizing the extensive u v-coverage provided by the array, coupled with the application of a recently developed superresolution imaging technique based on the regularized maximum-likelihood method, we were able to transversely resolve the NGC 315 jet at parsec scales for the first time. Previously known for its central ridge-brightened morphology at similar scales in former VLBI studies, the jet now clearly exhibits a limb-brightened structure. This finding suggests an inherent limb brightening that was not observable before due to limited angular resolution. Considering that the jet is viewed at an angle of ∼50°, the observed limb brightening is challenging to reconcile with the magnetohydrodynamic models and simulations, which predict that the Doppler-boosted jet edges should dominate over the nonboosted central layer. The conventional jet model that proposes a fast spine and a slow sheath with uniform transverse emissivity may pertain to our observations. However, in this model, the relativistic spine would need to travel at speeds of Γ ≳ 6.0–12.9 along the deprojected jet distance of (2.3–10.8) × 103 gravitational radii from the black hole. We propose an alternative scenario that suggests higher emissivity at the jet boundary layer, resulting from more efficient particle acceleration or mass loading onto the jet edges, and consider prospects for future observations with even higher angular resolution.

A high-resolution radio morphology and polarization of the kiloparsec-scale X-ray jet of PKS 1127−145

We report on new multifrequency Very Large Array (VLA) radio observations and Chandra X-ray observations of a radio-loud quasar with a ∼300 kpc-long jet, PKS 1127−145, during a flaring event detected in γ-rays by the Fermi Large Area Telescope in December 2020. The high angular resolution of the new radio images allows us to disentangle for the first time the kiloparsec-scale inner jet from the core contribution. The inner radio jet, up to 15 kpc from the core, is highly polarized (33 percent) and the magnetic field is parallel to the jet axis. At about 18 arcsecs from the core, the jet slightly bends and we observe a re-brightening of the radio emission and a 90-degree rotation of the magnetic field, likely highlighting the presence of a shock that is compressing the magnetic field to a plane perpendicular to the jet axis, where efficient particle acceleration takes place. At the same position, the X-ray emission fades, suggesting a deceleration of the bulk velocity of the jet after the bend. A change in velocity and collimation of the jet is supported by the widening of the jet profile and the detection of a limb-brightened structure connecting the bending region with the jet termination. The limb-brightened structure might indicate the coexistence of both longitudinal and transverse velocity gradients at the jet bending. There is no evidence of significant brightening of the kiloparsec-scale jet in the radio or X-ray band during the γ-ray flare. The X-ray flux, F2 − 10 keV = (6.24 ± 0.57)×10−12 ergs s−1 cm−2, measured by Chandra from the quasar core is consistent with the flux measured by the X-ray Telescope on board the Neil Gehrels Swift Observatory after the high-energy flare. Our results indicate that the γ-ray flaring region is located within the VLA source core.

Mass and wind luminosity of young Galactic open clusters in Gaia DR2

Context. Star clusters constitute a significant part of the stellar population in our Galaxy. The feedback processes they exert on the interstellar medium impact multiple physical processes from the chemical to the dynamical evolution of the Galaxy. In addition, young and massive stellar clusters might act as efficient particle accelerators and contribute to the production of cosmic rays. Aims. We aim at evaluating the wind luminosity driven by the young (< 30 Myr) Galactic open stellar clusters observed by the Gaia space mission. This is crucial for determining the energy channeled into accelerated particles. Methods. To do this, we developed a method relying on the number, magnitude, and line-of-sight extinction of the stars observed per cluster. Assuming that the stellar mass function follows a Kroupa mass distribution and accounting for the maximum stellar mass allowed by the age and mass of the parent cluster, we conservatively estimated the mass and wind luminosity of 387 local clusters within the second data release of Gaia. Results. We compared the results of our computation with recent estimates of young cluster masses. With respect to these, our sample is three times more abundant, particularly above a few thousand solar masses. This is of the utmost relevance for predicting the gamma-ray emission resulting from the interaction of accelerated particles. The cluster wind luminosity distribution we obtained extends up to 3 × 1038 erg s−1. This is a promising feature in terms of potential particle acceleration scenarios.

The population of Galactic supernova remnants in the TeV range

Supernova remnants (SNRs) are likely to be significant sources of cosmic rays up to the knee of the local cosmic-ray (CR) spectrum. They produce gamma rays in the very-high-energy (VHE) ($E>0.1$ TeV) range mainly via two mechanisms: hadronic interactions of accelerated protons with the interstellar medium and leptonic interactions of accelerated electrons with soft photons. Observations with current instruments have lead to the detection of about a dozen SNRs emitting VHE gamma rays and future instruments should significantly increase this number. Yet, the details of particle acceleration at SNRs and of the mechanisms producing VHE gamma-rays at SNRs remain poorly understood. We aim to study the population of SNRs detected in the TeV range and its properties and confront it to simulated samples in order to address fundamental questions concerning particle acceleration at SNR shocks. Such questions concern the spectrum of accelerated particles, the efficiency of particle acceleration, and the gamma-ray emission being dominated by hadronic or leptonic interactions. By means of Monte Carlo methods, we simulated the population of SNRs in the gamma--ray domain and confronted our simulations to the catalogue of sources from the High Energy Stereoscopic System (H.E.S.S.) Galactic Plane Survey (HGPS). We systematically explored the parameter space defined in our model, including for example, the slope of accelerated particles alpha , the electron-to-proton ratio $K_ ep $, and the efficiency of particle acceleration $ $. In particular, we found possible sets of parameters for which $ 90$<!PCT!> of Monte Carlo realisations are found to be in agreement with the HGPS. These parameters are typically found at $ 4.2 ep $, and $0.03 0.1 $ . We are able to strongly argue against some regions of the parameter space describing the population of Galactic SNRs in the TeV range, such as $ 4.35$, or ep Our model is so far able to explain the SNR population of the HGPS. Our approach, when confronted with the results of future systematic surveys, such as the Cherenkov Telescope Array Observatory, will help remove degeneracy from the solutions and to better understand particle acceleration at SNR shocks in the Galaxy.

First characterization of the emission behavior of Mrk 421 from radio to very high-energy gamma rays with simultaneous X-ray polarization measurements

Aims. We have performed the first broadband study of Mrk 421 from radio to TeV gamma rays with simultaneous measurements of the X-ray polarization from IXPE. Methods. The data were collected as part of an extensive multiwavelength campaign carried out between May and June 2022 using MAGIC, Fermi-LAT, NuSTAR, XMM-Newton, Swift, and several optical and radio telescopes to complement IXPE data. Results. During the IXPE exposures, the measured 0.2–1 TeV flux was close to the quiescent state and ranged from 25% to 50% of the Crab Nebula without intra-night variability. Throughout the campaign, the very high-energy (VHE) and X-ray emission are positively correlated at a 4σ significance level. The IXPE measurements reveal an X-ray polarization degree that is a factor of 2–5 higher than in the optical/radio bands; that implies an energy-stratified jet in which the VHE photons are emitted co-spatially with the X-rays, in the vicinity of a shock front. The June 2022 observations exhibit a rotation of the X-ray polarization angle. Despite no simultaneous VHE coverage being available during a large fraction of the swing, the Swift-XRT monitoring reveals an X-ray flux increase with a clear spectral hardening. This suggests that flares in high synchrotron peaked blazars can be accompanied by a polarization angle rotation, as observed in some flat spectrum radio quasars. Finally, during the polarization angle rotation, NuSTAR data reveal two contiguous spectral hysteresis loops in opposite directions (clockwise and counterclockwise), implying important changes in the particle acceleration efficiency on approximately hour timescales.

One-dimensional General Relativistic Particle-in-cell Simulations of Stellar-mass Black Hole Magnetospheres: A Semianalytic Model of Gamma-Rays from Gaps

In the absence of a sufficient amount of plasma injection into the black hole (BH) magnetosphere, the force-free state of the magnetosphere cannot be maintained, leading to the emergence of strong, time-dependent, longitudinal electric fields (i.e., spark gaps). Recent studies of supermassive BH magnetospheres using analytical methods and particle-in-cell (PIC) simulations propose the possibility of efficient particle acceleration and consequent gamma-ray emission in the spark gap. In this work, we perform 1D general relativistic PIC simulations to examine the gamma-ray emission from stellar-mass BH magnetospheres. We find that intermittent spark gaps emerge and particles are efficiently accelerated in a similar manner to the supermassive BH case. We build a semianalytic model of the plasma dynamics and radiative processes, which reproduces the maximum electron energies and peak gamma-ray luminosities of the simulation results. Based on this model, we show that the gamma-ray signals from stellar-mass BHs wandering through the interstellar medium could be detected by gamma-ray telescopes such as the Fermi Large Area Telescope or the Cherenkov Telescope Array.

The galactic bubbles of starburst galaxies

Context. The galactic winds of starburst galaxies (SBGs) give rise to remarkable structures on kiloparsec scales. However, the evolution and shape of these giant wind bubbles, as well as the properties of the shocks they develop, are not yet fully understood. Aims. We aim to understand what shapes the galactic winds of SBGs, with a particular focus on the role of large-scale magnetic fields in the dynamical evolution of galactic wind-inflated bubbles. In addition, we aim to explore where the conditions for efficient particle acceleration are met in these systems. Methods. We performed magnetohydrodynamic simulations with the AMRVAC code (Adaptive Mesh Refinement Versatile Advection Code) with various configurations of the galactic medium density profile and magnetization. Results. We observe that the large-scale magnetic field, in which galactic winds expand, can impact the structure and evolution of inflated bubbles. However, the typical structures observed in starburst galaxies, such as M82, cannot be solely explained by the magnetic field structures that have been considered. This highlights the importance of other factors, such as the galactic disk, in shaping the galactic bubble. Furthermore, in all the magnetized cases we investigated, the forward wave resulting from the expanding bubbles only results in compression waves, whereas the wind termination shock features high Mach numbers, making it a promising site for diffusive shock acceleration up to ∼102 PeV. The synthetic X-ray images generated from our models reveal an envelope surrounding the bubbles that extends up to 2 kpc, which could correspond to the polarized emission observed from planar geometry in M82, as well as a large structure inside the bubble corresponding to the shocked galactic wind. Additionally, our findings indicate that, as observed with the SOFIA instrument, a large ordered magnetic field is associated with the free galactic wind, while a more turbulent magnetic field is present in the shocked region.

Particle acceleration test with Cas A multiwavelength emission

AbstractThe investigation of supernova remnants (SNRs) across the electromagnetic spectrum from radio up to very high energy gamma‐rays can serve as a test of the particle acceleration and touches on one of the unresolved problems of modern astrophysics, namely the origin of cosmic rays and the Galaxy's contribution to the overall cosmic ray spectrum. The multiwavelength observations of Cas A SNR demonstrated that structure and spectral features have clear signs of young SNRs and its overall properties make this object the best target to test a hypothesis of cosmic ray origin in SNRs. Studies of Cas A at very high energies by SHALON telescope showed the location of TeV gamma‐ray emission region relative to the position of reveres shock. Also, the spectral energy distribution was obtained at high and very high energies. To describe the spectral and structural features of this SNR viewed in non‐thermal emission, two approaches involving reverse and also both reverse and forward shocks to the mechanism of diffusive shock acceleration of cosmic rays in Cas A were applied. It is demonstrated that the observational properties of Cas A are well reproduced by the hadronic model with significant contribution of both the forward and reverse shocks in the generation of broadband emission. Calculation results suggest that the very high efficiency of particle acceleration in Cas A, which value is up to 25% of the supernova explosion energy with energy of accelerated particles not exceeding of eV. Whereas, the forward shock model predicts the spectral characteristics of the TeV‐gamma‐emission corresponding to ones detected at 800 GeV–40 TeV that are the evidence of acceleration of the hadronic cosmic rays in shells of SNRs up to eV

Effektivnoe uskorenie elektronov femtosekundnymi lazernymi impul'sami umerennoy moshchnosti

The relativistic self-trapping of a laser pulse is an efficient mechanism for the acceleration of electrons, whichallows one to achieve an extreme charge of a high-energy particle beam and the corresponding conversioncoefficient of laser energy. It has been shown that the compression of the femtosecond laser pulse in thisregime using the innovative compression after compressor approach (CafCA) [E.A. Khazanov,S.Yu. Mironov, and G. Mourou, Phys. Usp. 62, 1096 (2019)] to extremely short durations keeping the energyof the laser beam significantly increases the efficiency of particle acceleration. This effect has been illustratedon the example of the Multitera laser facility for the project implemented at the Russian National Center forPhysics and Mathematics.

Probing the non-thermal physics of stellar bow shocks using radio observations

Context. Massive runaway stars produce bow shocks in the interstellar medium. Recent observations revealed radio emission from a few of these objects, but the origin of this radiation remains poorly understood. Aims. We aim to interpret this radio emission and assess under which conditions it could be either thermal (free–free) or non-thermal (synchrotron), and how to use the observational data to infer physical properties of the bow shocks. Methods. We used an extended non-thermal emission model for stellar bow shocks for which we incorporated a consistent calculation of the thermal emission from the forward shock. We fitted this model to the available radio data (spectral and intensity maps), including largely unexplored data at low frequencies. In addition, we used a simplified one-zone model to estimate the gamma-ray emission from particles escaping the bow shocks. Results. We can only explain the radio data from the best sampled systems (BD+43°3654 and BD+60°2522) assuming a hard electron energy distribution below ∼1 GeV, a high efficiency of conversion of (shocked) wind kinetic power into relativistic electrons (∼1 − 5%), and a relatively high magnetic-to-thermal pressure ratio of ηB ∼ 0.2. In the other systems, the interpretation of the observed flux density is more ambiguous, although a non-thermal scenario is also favoured. We also show how complementary observations at other frequencies can allow us to place stronger constraints in the model. We also estimated the gamma-ray fluxes from the HII regions around the bow shocks of BD+43°3654 and BD+60°2522, and obtained luminosities at GeV energies of ∼1033 erg s−1 and 1032 erg s−1, respectively, under reasonable assumptions. Conclusions. Stellar bow shocks can potentially be very efficient particle accelerators. This work provides multi-wavelength predictions of their emission and demonstrates the key role of low-frequency radio observations in unveiling particle acceleration processes. The prospects of detections with next-generation observatories such as SKA and ngVLA are very promising. Finally, BD+43°3654 may be detected in GeV in the near future, while bow shocks in general may turn out to be non-negligible sources of (at least leptonic) low-energy cosmic rays.

Synchrotron Polarization Signatures of Surface Waves in Supermassive Black Hole Jets

Supermassive black holes in active galactic nuclei are known to launch relativistic jets, which are observed across the entire electromagnetic spectrum and thought to be efficient particle accelerators. Their primary radiation mechanism for radio emission is polarized synchrotron emission produced by a population of nonthermal electrons. In this Letter, we present a global general relativistic magnetohydrodynamical (GRMHD) simulation of a magnetically arrested disk (MAD). After the simulation reaches the MAD state, we show that waves are continuously launched from the vicinity of the black hole and propagate along the interface between the jet and the wind. At this interface, a steep gradient in velocity is present between the mildly relativistic wind and the highly relativistic jet. The interface is, therefore, a shear layer, and due to the shear, the waves generate roll-ups that alter the magnetic field configuration and the shear layer geometry. We then perform polarized radiation transfer calculations of our GRMHD simulation and find signatures of the waves in both total intensity and linear polarization, effectively lowering the fully resolved polarization fraction. The telltale polarization signatures of the waves could be observable by future very long baseline interferometric observations, e.g., the next-generation Event Horizon Telescope.

Efficient Acceleration of Electrons by Moderate-Power Femtosecond Laser Pulses

The relativistic self-trapping of a laser pulse is an efficient mechanism for the acceleration of electrons, which allows one to achieve an extreme charge of a high-energy particle beam and the corresponding conversion coefficient of laser energy. It has been shown that the compression of the femtosecond laser pulse in this regime using the innovative compression after compressor approach (CafCA) [E.A. Khazanov, S.Yu. Mironov, and G. Mourou, Phys. Usp. 62, 1096 (2019)] to extremely short durations keeping the energy of the laser beam significantly increases the efficiency of particle acceleration. This effect has been illustrated on the example of the Multitera laser facility for the project implemented at the Russian National Center for Physics and Mathematics.

A Database of Magnetic and Thermodynamic Properties of Confined and Eruptive Solar Flares

Solar flares sometimes lead to coronal mass ejections that directly affect Earth's environment. However, a large fraction of flares, including on solar-type stars, are confined flares. What are the differences in physical properties between confined and eruptive flares? For the first time, we quantify the thermodynamic and magnetic properties of hundreds of confined and eruptive flares of GOES class C5.0 and above, 480 flares in total. We first analyze large flares of GOES class M1.0 and above observed by the Solar Dynamics Observatory, 216 flares in total, including 103 eruptive and 113 confined flares, from 2010 until 2016 April; we then look at the entire data set of 480 flares above class C5.0. We compare GOES X-ray thermodynamic flare properties, including peak temperature and emission measure, and active-region (AR) and flare-ribbon magnetic field properties, including reconnected magnetic flux and peak reconnection rate. We find that for fixed peak X-ray flux, confined and eruptive flares have similar reconnection fluxes; however, for fixed peak X-ray flux confined flares have on average larger peak magnetic reconnection rates, are more compact, and occur in larger ARs than eruptive flares. These findings suggest that confined flares are caused by reconnection between more compact, stronger, lower-lying magnetic fields in larger ARs that reorganizes a smaller fraction of these regions’ fields. This reconnection proceeds at faster rates and ends earlier, potentially leading to more efficient flare particle acceleration in confined flares.

Preparation of C-S-H-PCE composites using an impinging stream reactor

The C-S-H-PCE composites (CPCs) serve as an accelerator for cement hydration. This work presents a novel approach for synthesizing CPCs using an impinging stream reactor (ISR). The resulting CPCs exhibited an average particle size of approximately 21 nm and significantly enhanced the compressive strength of mortar when used as an additive. The compressive strength value of the mortar after curing for 6 h is 18.7 N/mm2, which is 503 % higher than the control group. Moreover, the ISR method was superior to the conventional stirred tank reactor method in terms of product particle size and acceleration efficiency.

Mirror Acceleration of Cosmic Rays in a High-β Medium

In a weakly compressible high-β medium, pitch-angle scattering and the associated scattering acceleration of cosmic rays (CRs) by anisotropic Alfvén and slow modes of magnetohydrodynamic (MHD) turbulence is inefficient. To tap the energy from magnetic compressions for efficient particle acceleration, a diffusion mechanism that can effectively confine particles in space without causing their trapping or pitch-angle isotropization is needed. We find that the mirror diffusion in MHD turbulence recently identified in Lazarian & Xu satisfies all the above conditions and serves as a promising diffusion mechanism for efficient acceleration of CRs via their stochastic nonresonant interactions with magnetic compressions/expansions. The resulting mirror acceleration is dominated by the slow-mode eddies with their lifetime comparable to the mirror diffusion time of CRs. Consequently, we find that the acceleration time of mirror acceleration is independent of the spatial diffusion coefficient of CRs. The mirror acceleration brings new life for the particle acceleration in a weakly compressible/incompressible medium and has important implications for studying CR reacceleration in the high-β intracluster medium.

Electron Heating in Shocks: Statistics and Comparison

AbstractSupernova remnant (SNR) shocks are the highest Mach number non‐relativistic shocks in electron‐ion plasmas. These shocks are the most efficient particle accelerators in space. SNR shock parameters are inferred from measurements of electromagnetic radiation from heated and accelerated particles. Temperature of the shock heated electrons is one of the most important parameters in supernova remnant shocks. Knowledge of the downstream electron‐to‐ion temperature ratio or of the ratio of the downstream electron temperature to the incident ion energy is crucial for understanding physics of the very high‐Mach number SNR shocks. Heliospheric shocks have substantially lower Mach numbers than SNR shocks but can be extensively studied in in situ observations with further extrapolation of the findings to higher Mach numbers. Magnetospheric Multiscale mission observations of the Earth bow shock are used to analyze dependence of the electron heating on the shock Mach number. It is found that the ratio of the downstream electron temperature to the incident ion energy decreases with the increase of the Mach number. At high Mach numbers this ratio and stabilizes at about 2.5%. The electron‐to‐ion temperature ratio stabilizes at about 10%. The peak electron temperature occurs at the overshoot maximum, further downstream electrons cool down. The mean ratio of the 4.5 s averages of the downstream and maximum electron temperatures is 0.85. Electron heating does not follow the thermodynamic adiabatic law. The heating and cooling behavior implies that the energy is provided by the overall cross‐shock potential while small‐scale electric fields rapidly isotropize the electron distribution.

The Role of Magnetic Shear in Reconnection-driven Flare Energy Release

Using observations from the Solar Dynamics Observatory’s Atmosphere Imaging Assembly and the Ramaty High Energy Solar Spectroscopic Imager, we present novel measurements of the shear of post-reconnection flare loops (PRFLs) in SOL20141218T21:40 and study its evolution with respect to magnetic reconnection and flare emission. Two quasi-parallel ribbons form adjacent to the magnetic polarity inversion line (PIL), spreading in time first parallel to the PIL and then mostly in a perpendicular direction. We measure the magnetic reconnection rate from the ribbon evolution, and also the shear angle of a large number of PRFLs observed in extreme ultraviolet passbands (≲1 MK). For the first time, the shear angle measurements are conducted using several complementary techniques allowing for cross validation of the results. In this flare, the total reconnection rate is much enhanced before a sharp increase in the hard X-ray emission, and the median shear decreases from 60°–70° to 20°, on a timescale of 10 minutes. We find a correlation between the shear-modulated total reconnection rate and the nonthermal electron flux. These results confirm the strong-to-weak shear evolution suggested in previous observational studies and reproduced in numerical models, and also confirm that, in this flare, reconnection is not an efficient producer of energetic nonthermal electrons during the first 10 minutes when the strongly sheared PRFLs are formed. We conclude that an intermediate shear angle, ≤40°, is needed for efficient particle acceleration via reconnection, and we propose a theoretical interpretation.

Particles in Relativistic MHD Jets. I. Role of Jet Dynamics in Particle Acceleration

Relativistic jets from (supermassive) black holes are typically observed in nonthermal emission, caused by highly relativistic electrons. Here, we study the interrelation between three-dimensional (special) relativistic magnetohydrodynamics, and particle acceleration in these jets. We inject Lagrangian particles into the jet that are accelerated through diffusive shock acceleration and radiate energy via synchrotron and inverse Compton processes. We investigate the impact of different injection nozzles on the jet dynamics, propagation, and the spectral energy distribution of relativistic particles. We consider three different injection nozzles—injecting steady, variable, and precessing jets. These jets evolve with substantially different dynamics, driving different levels of turbulence and shock structures. The steady jet shows a strong, stationary shock feature, resulting from a head-on collision with an inner back-flow along the jet axis—a jet inside a jet. This shock represents a site for highly efficient particle acceleration for electrons up to a few tens of TeV and should be visible in emission as a jet knot. Overall, we find that the total number of shocks is more essential for particle acceleration than the strength of the shocks. The precessing jet is most efficient in accelerating electrons to high energies reaching even few hundred TeVs, with power-law index ranging from 2.3 to 3.1. We compare different outflow components, such as the jet and the entrained material concerning particle acceleration. For the precessing nozzle, the particle acceleration in the entrained material is as efficient as that in the jet stream. This is due to the higher level of turbulence induced by the precession motion.