For near-future missions planed for Mars Sample Return (MSR), an international working group organized by the Committee on Space Research (COSPAR) developed the sample safety assessment framework (SSAF). For the SSAF, analytical instruments were selected by taking the practical limitations of hosting them within a facility with the highest level of biosafety precautions (biosafety level 4) and the precious nature of returned samples into account. To prepare for MSR, analytical instruments of high sensitivity need to be tested on effective Mars analogue materials. As an analogue material, we selected a rock core of basalt, a prominent rock type on the Martian surface. Two basalt samples with aqueous alteration cached in Jezero crater by the Perseverance rover are planned to be returned to Earth. Our previously published analytical procedures using destructive but spatially sensitive instruments such as nanoscale secondary ion mass spectrometry (NanoSIMS) and transmission electron microscopy coupled to energy-dispersive spectroscopy revealed microbial colonization at clay-filled fractures. With an aim to test the capability of an analytical instrument listed in SSAF, we now extend that work to conventional Fourier transform infrared (FT-IR) microscopy with a spatial resolution of 10 μm. Although Fe-rich smectite called nontronite was identified after crushing some portion of the rock core sample into powder, the application of conventional FT-IR microscopy is limited to a sample thickness of <30 μm. In order to obtain IR-based spectra without destructive preparation, a new technique called optical-photothermal infrared (O-PTIR) spectroscopy with a spatial resolution of 0.5 μm was applied to a 100 μm thick section of the rock core. By O-PTIR spectroscopic analysis of the clay-filled fracture, we obtained in-situ spectra diagnostic to microbial cells, consistent with our previously published data obtained by NanoSIMS. In addition, nontronite identification was also possible by O-PTIR spectroscopic analysis. From these results, O-PTIR spectroscopy is suggested be superior to deep ultraviolet fluorescence microscopy/μ-Raman spectroscopy, particularly for smectite identification. A simultaneous acquisition of the spatial distribution of structural motifs associated with biomolecules and smectites is critical for distinguishing biological material in samples as well as characterizing an abiotic background.

Thanks to advances in plasma science and enabling technology, mirror machines are being reconsidered for fusion power plants and as possible fusion volumetric neutron sources. However, cross-field transport and turbulence in mirrors remains relatively understudied compared with toroidal devices. Turbulence and transport in mirror configurations were studied utilizing the flexible magnetic geometry of the Large Plasma Device (LAPD). Multiple mirror ratios from $M=1$ to $M=2.68$ and three mirror-cell lengths from $L=3.51$ to $L=10.86$ m were examined. Langmuir and magnetic probes were used to measure profiles of density, temperature, potential and magnetic field. The electric field-fluctuation-driven ${\tilde {\boldsymbol{E}}} \times {\boldsymbol{B}}$ particle flux, where $\boldsymbol{B}$ is the background field, was calculated from these quantities. Two probe correlation techniques were used to infer wavenumbers and two-dimensional structure. Cross-field particle flux and density fluctuation power decreased with increased mirror ratio. Core density and temperatures remain similar with mirror ratio, but radial line-integrated density increased. The physical expansion of the plasma in the mirror cell by using a higher field in the source region may have led to reduced density fluctuation power through the increased gradient scale length. This increased scale length reduced the growth rate and saturation level of rotational interchange and drift-like instabilities. Despite the introduction of magnetic curvature, no evidence of mirror-driven instabilities – interchange, velocity space or otherwise – were observed. For curvature-induced interchange, many possible stabilization mechanisms were present, suppressing the visibility of the instability.

The betatron radiation source features a micrometer-scale source size, a femtosecond-scale pulse duration, milliradian-level divergence angles and a broad spectrum exceeding tens of keV. It is conducive to the high-contrast imaging of minute structures and for investigating interdisciplinary ultrafast processes. In this study, we present a betatron X-ray source derived from a high-charge, high-energy electron beam through a laser wakefield accelerator driven by the 1 PW/0.1 Hz laser system at the Shanghai Superintense Ultrafast Laser Facility (SULF). The critical energy of the betatron X-ray source is 22 ± 5 keV. The maximum X-ray flux reaches up to 4 × 109 photons for each shot in the spectral range of 5–30 keV. Correspondingly, the experiment demonstrates a peak brightness of 1.0 × 1023 photons·s−1·mm−2·mrad−2·0.1%BW−1, comparable to those demonstrated by third-generation synchrotron light sources. In addition, the imaging capability of the betatron X-ray source is validated. This study lays the foundation for future imaging applications.

Traditional wavefront control in high-energy, high-intensity laser systems usually lacks real-time capability, failing to address dynamic aberrations. This limits experimental accuracy due to shot-to-shot fluctuations and necessitates long cool-down phases to mitigate thermal effects, particularly as higher repetition rates become essential, for example, in inertial fusion research. This paper details the development and implementation of a real-time capable adaptive optics system at the Apollon laser facility. Inspired by astronomical adaptive optics, the system uses a fiber-coupled 905 nm laser diode as a pilot beam that allows for spectral separation, bypassing the constraints of pulsed lasers. A graphics processing unit-based controller, built on the open-source Compute And Control for Adaptive Optics framework, manages a loop comprising a bimorph deformable mirror and a high-speed Shack–Hartmann sensor. Initial tests showed excellent stability and effective aberration correction. However, integration into the Apollon laser revealed critical challenges unique to the laser environment that must be resolved to ensure safe operation with amplified shots.

Quantum algorithms have been proposed to accelerate the simulation of the chaotic dynamical systems that are ubiquitous in the physics of plasmas. Quantum computers without error correction might even use noise to their advantage to calculate the Lyapunov exponent by measuring the Loschmidt echo fidelity decay rate. For the first time, digital Hamiltonian simulations of the quantum sawtooth map, performed on the IBM-Q quantum hardware platform, show that the fidelity decay rate of a digital quantum simulation increases during the transition from dynamical localization to chaotic diffusion in the map. The observed error per CNOT gate increases by $1.5{\times }$ as the dynamics varies from localized to diffusive, while only changing the phases of virtual RZ gates and keeping the overall gate count constant. A gate-based Lindblad noise model that captures the effective change in relaxation and dephasing errors during gate operation qualitatively explains the effect of dynamics on fidelity as being due to the localization and entanglement of the states created. Specifically, highly delocalized states that are entangled with random phases show an increased sensitivity to dephasing and, on average, a similar sensitivity to relaxation as localized states. In contrast, delocalized unentangled states show an increased sensitivity to dephasing but a lower sensitivity to relaxation. This gate-based Lindblad model is shown to be a useful benchmarking tool by estimating the effective Lindblad coherence times during CNOT gates and finding a consistent $2\unicode{x2013}3{\times }$ shorter $T_2$ time than reported for idle qubits. Thus, the interplay of the dynamics of a simulation with the noise processes that are active can strongly influence the overall fidelity decay rate.

The design of fusion devices is typically based on computationally expensive simulations. This can be alleviated using high aspect ratio models that employ a reduced number of free parameters, especially in the case of stellarator optimization where non-axisymmetric magnetic fields with a large parameter space are optimized to satisfy certain performance criteria. However, optimization is still required to find configurations with properties such as low elongation, high rotational transform, finite beta and good fast particle confinement. In this work, we train a machine learning model to construct configurations with favourable confinement properties by finding a solution to the inverse design problem, that is, obtaining a set of model input parameters for given desired properties. Since the solution of the inverse problem is non-unique, a probabilistic approach, based on mixture density networks, is used. It is shown that optimized configurations can be generated reliably using this method.

Motivated by explosive releases of energy in fusion, space and astrophysical plasmas, we consider the nonlinear stability of stratified magnetohydrodynamic equilibria against two-dimensional interchanges of straight magnetic-flux tubes. We demonstrate that, even within this restricted class of dynamics, the linear stability of an equilibrium does not guarantee its nonlinear stability: equilibria can be metastable. We show that the minimum-energy state accessible to a metastable equilibrium under non-diffusive two-dimensional dynamics can be found by solving a combinatorial optimisation problem. These minimum-energy states are, to good approximation, the final states reached by our simulations of destabilised metastable equilibria for which turbulent mixing is suppressed by viscosity. To predict the result of fully turbulent relaxation, we construct a statistical mechanical theory based on the maximisation of Boltzmann's mixing entropy. This theory is analogous to the Lynden-Bell statistical mechanics of collisionless stellar systems and plasma, and to the Robert–Sommeria–Miller theory of two-dimensional vortex turbulence. Our theory reproduces well the results of our numerical simulations for sufficiently large perturbations to the metastable equilibrium.

The heat conductivity of a plasma is usually much higher along the magnetic field than across it, and, as a result, the presence of a magnetic island can significantly affect the temperature profile in its vicinity. Radiation energy losses, which depend sensitively on temperature, are thus strongly affected by magnetic islands. This phenomenon is explored in a simple mathematical setting, and it is shown that the presence of a magnetic island greatly enhances a plasma's capacity to radiate energy. In the limit of highly anisotropic heat conductivity, the steady-state heat conduction equation can be reduced to an ordinary differential equation. Although this equation operates in one dimension, the topology is not that of the real line, but corresponds to a rod with a cooling fin. As parameters such as the incoming heat flux or the radiation amplitude are varied, the radiation has a tendency to linger around the island, in particular in the region of the separatrix, and the total radiated energy is then significantly increased. The island acts as a ‘cooling fin’ to the plasma. Furthermore, the solutions exhibit bifurcations, where the location of the radiation zone suddenly changes.

Electron cyclotron resonance ion thrusters (ECRITs) have the potential to be used for space gravitational wave detection due to their wide thrust range. However, an unclear understanding of dynamic processes of ECRITs with strongly coupled multi-operating parameters limits further improvements on thrust noise and response velocity by feedback control systems. An integrative mathematical model considering the non-Maxwell electron energy distribution function for ECRITs is validated by experiments and used to study the influence of operating parameters on the dynamic processes of thrusters, which provides a new simplified grid model. Simulation results show the response processes with microwave (MW) power can be divided into two stages. The characteristic times of the first and second stages are respectively several microseconds and 10 ms, which are respectively dominated by plasma motion and the volume effect. The overshoot of screen grid (SG) current decreases, while its response time remains unchanged when the response time of MW power is prolonged. The response time of SG current with a step increase of flow rate is approximately 10 ms, consistent with the volume effect. The SG current decreases with rise of flow rate for high flow rate operations due to the small increment of ion density limited by low electron temperature, the decrease of ion Bohm velocity and reduction of sheath extraction area. The influence of grid voltage on the dynamic process of the SG current depends on variation ranges of extraction capabilities. When variations of sheath extraction area are limited, the response time is 5 μs, consistent with plasma response time. It is prolonged to 0.5 ms if sheath extraction area variations are large because they cause obvious variations of plasma parameters in the discharge chamber. These dynamic results can not only facilitate designing feedback controllers of micro-propulsion systems for high-precision space missions, but also provide guidance for ion sources to generate highly stable or rapid-response ion beam.