This work uses topology optimization methods to interactively design the plasma and metasurface loaded by resistance film, and obtains a composite absorber with good absorption effect. Genetic algorithm is used to find the minimum reflectivity of the composite absorber of plasma and metasurfaces, and after decoding, determine the corresponding topological structure of metasurface units and the optimal values of other parameters of the composite absorber. The optimized composite absorber maintains an absorption rate of over 95% in a wide frequency range of 5 GHz–18 GHz. This broadband absorption effect is caused by the superposition of the absorption performance of plasma and metasurface. In addition, due to the central symmetric configuration of the metasurface unit, the composite absorber has good polarization insensitivity characteristics, and it still has broadband absorbing ability in the case of TE polarized waves and TM polarized waves obliquely incident. Thus, the proposed composite absorber designed based on topology optimization method has a wide frequency band, wide incidence angle, high absorption rate, and polarization insensitive absorbing effect. The topology optimization method is used for the design of the proposed composite absorber composed of plasma and metasurface, which does not overly rely on design experience of designer and provides an intelligent design method for stealth skin design in complex scattering media such as plasma.

This work clarifies the systematic relationship and difference mechanism between flight speed, plasma sheath and terahertz transmission under different vehicle types by joint simulation model of hypersonic plasma flow and improved scattering matrix method. Significant differences in plasma sheath and terahertz transmission characteristics are observed in different vehicle types. Radio Attenuation Measurement C (RAM C) vehicle has a larger collision frequency and sheath thickness, resulting in higher terahertz attenuation than Hypersonic International Flight Research Experimentation (HIFiRE) vehicle. With the increase of flight speed, electron density, collision frequency and terahertz attenuation of the two different types of vehicles all show a significant increase, and the sheath thickness shows an opposite trend. However, the impact of flight speed on HIFiRE vehicle is much smaller than that on RAM C vehicle, which means that flight parameters have higher control accuracy for RAM C vehicle. On this basis, the systematic relationship between plasma sheath distribution and flight speed is further determined, and a rapid prediction model for terahertz transmission attenuation of different types of vehicle is developed based on a large amount of plasma sheath data. The rapid prediction model greatly reduces the calculation time and resources compared with traditional numerical methods, and its related prediction coefficients show significant differences on different vehicle types.

In ground-based astronomical observations or artificial space target detections, images obtained from a ground-based telescope are severely distorted due to atmospheric turbulence. The distortion can be partially compensated by employing adaptive optics (pre-detection compensation), image restoration techniques (post-detection compensation), or a combination of both (hybrid compensation). This paper focuses on the improvement of the most commonly used practical post-processing techniques, Richardson–Lucy (R–L) iteration blind deconvolution, which is studied in detail and improved as follows: First, the total variation (TV) norm is redefined using the Gaussian gradient magnitude and a set scheme for regularization parameter selection is proposed. Second, the Gaussian TV constraint is proposed to impose to the R–L algorithm. Last, the Gaussian TV R–L (GRL) iterative blind deconvolution method is finally presented, in which the restoration precision is visually increased and the convergence property is considerably improved. The performance of the proposed GRL method is tested by both simulation experiments and observed field data.

A dual-wavelength spaceborne Martian polarized wind imaging Michelson interferometer based on liquid crystal tunable filters (LCTF-MPWIMI) has been proposed for the remote sensing detection of dynamic parameters such as wind speed and temperature in the middle and upper atmosphere of Mars. Using the detected Martian oxygen atom emission lines at 557.7 nm and 630.0 nm as observation spectral lines, this technology extends the detection altitude range for Martian atmospheric wind speed and temperature to 60–180 km. By leveraging the different spectral line visibility of the interferograms at the two wavelengths, a novel method for measuring Martian atmospheric temperature is proposed: the dual-wavelength spectral line visibility product method. This new approach reduces the uncertainty of temperature detection compared to traditional single spectral line visibility methods, while maintaining the precision of wind speed measurements. The feasibility of the LCTF-MPWIMI for measuring wind and temperature fields in the Martian middle and upper atmosphere has been validated through theoretical modeling and computer simulations. The interferometer, as a key component of the system, has been designed and analyzed. The proposed LCTF-MPWIMI instrument is free of mechanical moving parts, offering flexible wavelength selection and facilitating miniaturization. The dual-wavelength temperature measurement method introduced in this work provides superior temperature measurement precision compared to any single spectral line when the signal-to-noise ratio (SNR) of the interferograms is comparable. Moreover, this method does not impose specific requirements on the atomic state of the spectral lines, making it broadly applicable to similar interferometric wind measurement instruments. These innovations offer advanced tools and methodologies for measuring wind speeds and temperatures in the atmospheres of Mars and other planets.

The disturbance flow field arises naturally with hypersonic target flying in near space. In situations where traditional infrared and radar systems lose effectiveness, space-based optical detection of this surrounding flow can serve as an alternative method for detecting high-speed targets. This paper presents a remote sensing imaging analysis of the disturbance flow field surrounding a hypersnoic target at different flight altitudes and Mach numbers. Utilizing Fourier Optics and Background-Oriented Schlieren, in conjunction with the fourth-order Runge-Kutta ray tracing algorithm, the imaging blurring and imaging deviation of three typical backgrounds under the influence of the disturbance flow field are obtained. Additionally, the study analyzes the influence of flight conditions and parameters of the imaging system on the imaging characteristics, and provides optical design recommendations. The results indicate that the presence of disturbance flow fields leads to varying degrees of visually apparent blurring effects and indiscernible deviation effects on the background images. Furthermore, the profiles of the disturbance flow field are extracted, in agreement with current experimental research. This study verifies the feasibility of space-based optical detection of hypersonic targets through disturbance flow field remote sensing imaging and contributes to the advancement of imaging research in this field.