Field Components Research Articles

A Discrimination method of three types of defects in insulated cladding components based on the lift-off effect of capacitive imaging (CI) technology

In insulated cladding components, simultaneously detecting and distinguishing surface defects on the insulation layer, hidden defects in the insulation layer, and surface defects on the metal layer of insulated cladding components can help in formulating appropriate maintenance plans and promptly eliminating safety hazards, which is of great significance for ensuring the safety of insulated cladding components in relevant application fields. This paper applies capacitive imaging (CI) to detect three different types of defects. A three-dimensional simulation model of the CI sensor detecting the three types of defects is established using COMSOL software. The corresponding measurement sensitivity distribution (MSD) and volume of influence (VOI) are obtained, and the detection mechanisms of the three different types of defects are analyzed in detail. By analyzing the lift-off height variation, the VOI regions' changing patterns for different types of defects are determined, and the distinguishing mechanisms for the three types of defects are obtained. Based on the monotonicity of the normalized variation ratio (NVR) and the differences in the positions of the intersection points, a comparative distinguishing method for the three types of defects based on the variation of the lift-off height is established. Experimental results demonstrate that the defect comparative distinguishing method based on the lift-off effect can effectively differentiate surface defects on the insulation layer, hidden defects in the insulation layer, and surface defects on the metal layer.

Numerical modelling of the IMF influence on the large-scale structure of the ionosphere, including the poles displacement

The interplanetary magnetic field (IMF), frozen into the solar wind plasma, determines the level of geomagnetic activity and significantly affects the large-scale structure of the high-latitude ionosphere. Variations in the IMF components lead to non-stationarity of the magnetospheric convection electric field, causing changes in the spatio-temporal distribution of charged particles in the ionosphere. The situation is complicated by the fact that the geographic and geomagnetic poles do not coincide, which leads to universal time control (UT control) of the parameters of the high-latitude ionosphere. The effect of the poles displacement is most manifest in winter. Therefore, in this work, within the framework of a nonstationary mathematical model of the F-region of the ionosphere in Euler variables, taking into account the displacement between the geographic and geomagnetic poles, we study the influence of the interplanetary magnetic field components on the large-scale structure of the high-latitude ionosphere in winter. For this, the Weimer model of high-latitude electric potentials, which depends on the IMF, was used. As a result, of numerical modelling, it is shown that the IMF components affect the shape, size and spatio-temporal location of the main structural features of the high-latitude ionosphere depending on universal time. The obtained effect of ionisation tongue separation requires experimental confirmation. The obtained results demonstrate that the developed non-stationary three-dimensional model of the ionosphere in Euler variables can be applied to the study of ionospheric disturbances, including ionospheric disturbances associated with changes in the IMF components.

3D polarization-interference holographic histology for wavelet-based differentiation of the polycrystalline component of biological tissues with different necrotic states. Forensic applications.

The interference-holographic method of phase scanning of fields of scattered laser radiation is proposed. The effectiveness of this method for the selection of variously dispersed components is demonstrated. This method made it possible to obtain polarization maps of biological tissues at a high level of depolarized background. The scale-selective analysis of such maps was used to determine necrotic changes in the optically anisotropic architectonics of biological tissues. Development and experimental approbation of layered phase polarimetry of repeatedly scattered fields in diffuse layers of biological tissues. Application of scale-selective processing of the found coordinate distributions of polarization states in various phase sections of object fields. Determination of criteria (markers) for histological differential diagnosis of the causes of necrotic changes in optical anisotropy of biological tissues. We used a synthesis of three instrumental and analytical methods. Polarization-interference registration of laser radiation scattered by a sample of biological tissue. Digital holographic reconstruction and layered phase scanning of distributions of complex amplitudes of the object field. Analytical determination of polarization maps of various phase cross-sections of repeatedly scattered radiation. Application of wavelet analysis of the distributions of polarization states in the phase plane of a single scattered component of an object field. Determination of criteria (markers) for differential diagnosis of necrotic changes in biological tissues with different morphological structure. Two cases are considered. The first case is the myocardium of those who died as a result of coronary heart disease and acute coronary insufficiency. The second case is lung tissue samples of deceased with bronchial asthma and fibrosis. A method of polarization-interference mapping of diffuse object fields of biological tissues has been developed and experimentally implemented. With the help of digital holographic reconstruction of the distributions of complex amplitudes, polarization maps in various phase sections of a diffuse object field are found. The wavelet analysis of azimuth and ellipticity distributions of polarization in the phase plane of a single scattered component of laser radiation is used. Scenarios for changing the amplitude of the wavelet coefficients for different scales of the scanning salt-like MHAT function are determined. Statistical moments of the first to fourth orders are determined for the distributions of the amplitudes of the wavelet coefficients of the azimuth maps and the ellipticity of polarization. As a result, diagnostic markers of necrotic changes in the myocardium and lung tissue were determined. The statistical criteria found are the basis for determining the accuracy of their differential diagnosis of various necrotic states of biological tissues. Necrotic changes caused by "coronary artery disease-acute coronary insufficiency" and "asthma-pulmonary fibrosis" were demonstrated by the method of wavelet differentiation with polarization interference with excellent accuracy.

A novel design of hard-magnetic soft switch array for planar and curved surface applications

This paper proposes an array structure with multidirectional remanent magnetization based on hard-magnetic soft materials, which can be used as a soft switch array on planar and curved surfaces. We firstly investigate the displacement response of a hard-magnetic soft switch which is excited by a magnetic field, and related to the magnitude and direction of the magnetic field. When the remanent magnetization direction of the soft switch is opposite to the horizontal component of the magnetic field, the displacement response is greater than that of the driving magnetic field in other directions. The maximum displacement of the soft switch can reach 4.5 mm under a 6 V driving voltage applied to the Helmholtz coil. We further design 2 × 2 and 3 × 3 switch arrays and the circuit structures of the switch arrays. The switch arrays are fabricated, and the displacement responses of the switch arrays under different driving magnetic fields on planar and curved surfaces are finally demonstrated. When the Z-axis displacement of the device reaches more than 3 mm, the LED light can be switched on. The hard-magnetic soft switch array structure designed in this paper can enable the application of soft switches in curved environments, verifying the feasibility of the application of hard-magnetic soft switch arrays. It is expected to provide a guidance for the design and manufacturing of multi-functional hard-magnetic soft switches in the future and the application of hard-magnetic soft switch arrays in planar and curved environments.

Distributed optical fiber magnetic field sensor based on polarization-sensitive OFDR.

A distributed optical fiber magnetic field sensor based on a polarization-sensitive optical frequency domain reflectometer (POFDR) is proposed. It extracts the accumulated Faraday rotation by combining the Stokes vectors and the backward Mueller matrices from the measured states of polarization (SOPs) and obtains the magnetic field component. This method avoids adjusting the input polarization during the magnetic field sensing process. It overcomes the drawback of the conventional POFDR scheme, which requires at least two sets of different input SOPs for each sensing. Finally, the aforementioned effectiveness has been experimentally verified by using a single-mode sensing fiber. The results show that the sensor has good repeatability and linearity. The measurement error of the magnetic field sensor is 19.4 mT. The measured magnetic field variations agree with the applied ones with similarities higher than 0.98.

Subwavelength dielectric waveguide for efficient travelling-wave magnetic resonance imaging

Magnetic resonance imaging (MRI) has diverse applications in physics, biology, and medicine. Uniform excitation of nuclei spins through circular-polarized transverse magnetic component of electromagnetic field is vital for obtaining unbiased tissue contrasts. However, achieving this in the electrically large human body poses a significant challenge, especially at ultra-high fields (UHF) with increased working frequencies (≥297 MHz). Canonical volume resonators struggle to meet this challenge, while radiative excitation methods like travelling-wave (TW) show promise but often suffer from inadequate excitation efficiency. Here, we introduce a new technique using a subwavelength dielectric waveguide insert that enhances both efficiency and homogeneity at 7 T. Through TE11-to-TM11 mode conversion, power focusing, wave impedance matching, and phase velocity matching, we achieved a 114% improvement in TW efficiency and mitigated the center-brightening effect. This fundamental advancement in TW MRI through effective wave manipulation could promote the electromagnetic design of UHF MRI systems.

Integrable coupled bosonic massive Thirring model and its nonlocal reductions

A coupled bosonic massive Thirring model (BMTM), involving an interaction between the two independent spinors, is introduced and shown to be integrable. By incorporating suitable reductions between the field components of the coupled BMTM, five novel integrable models with various type of nonlocal interactions are constructed. Lax pairs satisfying the zero curvature condition are obtained for the coupled BMTM and for each of the related nonlocal models. An infinite number of conserved quantities are derived for each of these models which confirms the integrability of the systems. It is shown that the coupled BMTM respects important symmetries of the original BMTM such as parity, time reversal, global U(1)-gauge and the proper Lorentz transformations. Similarly, all the nonlocal models obtained from the coupled BMTM remain invariant under combined operation of parity and time reversal transformations. However, it is found that only one of the nonlocal models is invariant under proper Lorentz transformation and two other models are invariant under global U(1)-gauge transformation. By using ultralocal Poisson bracket relations among the elements of the Lax operator, it is shown that the coupled BMTM and one of the nonlocal models are completely integrable in the Liouville sense.

Quasi-planar ICME sheath: A cause of the first two-step extreme geomagnetic storm of the 25th solar cycle observed on 23 April 2023

Interplanetary Coronal Mass Ejections (ICMEs) are prominent drivers of space weather disturbances. The reported studies suggested that the planar ICME sheath and planar magnetic clouds (MCs) cause extreme geomagnetic storms. Here, we investigated the first two-step extreme geomagnetic storm (Sym-H∼-231 nT) of 25th solar cycle. Our analysis demonstrates the transformation of ICME sheath into quasi-planar magnetic structures (PMS). The study corroborates our earlier reported finding that the less adiabatic expansion in possible quasi-PMS transformed ICME enhanced the strength of the southward magnetic field component. It contributes to the efficient transfer of plasma and energy in the Earth’s magnetosphere to cause the observed extreme storm. We found that the magnetosphere stand-off distance reduced to <6RE (where RE stands for the Earth’s radius), and it impacts geosynchronous satellites moving close to 6RE.

Time-dependent model of temperature distribution in continuous flow pulsed electric field treatment chambers

A key component of a continuous flow pulsed electric field (PEF) system is the treatment chamber, where the product is exposed to electric pulses. Determination of the temperature distribution in the chamber during PEF treatment is important since high local increases in temperatures can affect the quality of the product. Coupled simulations of electric field, fluid flow, and heating in the existing literature do not model each individual electric pulse, but rather employ a “duty cycle” approach, which does not account for transient variations in treatment intensity and temperature changes in the medium. We present a time-dependent approach to modelling PEF treatment in continuous flow treatment chambers, which can model each pulse separately, and thus enables a more accurate study of temporal and spatial distributions of electric field and temperature. The model has been validated on laboratory scale treatment chambers of parallel plate or colinear design and using realistic protocols. Industrial relevance textThe paper is relevant to all pulsed electric field (PEF) applications either on laboratory or industrial scale that implement a continuous flow treatment chamber. It presents an improved modelling approach which allows for an analysis of the electrical current, electric field, and temperature distribution in the chamber during, at the end, and in between application of electrical pulses. The model can be used to predict the peak temperature at the end of each pulse in the hot spots, which if large enough could potentially lead to thermal damage of the product or in extreme cases even potential local boiling of the medium, resulting not only in degradation of the treated product, but also in accelerated electrode fouling, oxidation, and dissolution (etching), as well as arcing. This would not only affect the quality of the treated product but would also affect the wear and lifetime of electrodes/chambers, and of the pulse generator. The model can also be used to avoid expensive trial-and-error optimization of the PEF protocols and chamber geometries in situ.

Determination of the magnetization direction via correlation between reduced‐to‐the‐pole magnetic anomalies and total gradient of the magnetic potential with vertical magnetization

AbstractThe total magnetization of an underground magnetic source is the vector sum of the induced magnetization and the natural remanent magnetization. The direction of the total magnetization serves as important a priori information in the inversion and processing of magnetic data. We demonstrated that the total gradient of the magnetic potential with vertical magnetization constitutes the envelope of the vertical component of the magnetic field for all directions of the Earth's field and source magnetization. The total gradient of the magnetic potential with vertical magnetization and the reduction‐to‐the‐pole field simultaneously tend to achieve maximum symmetry near the correct total magnetization direction. As a result, the total magnetization direction can be estimated by computing the correlations between the reduction‐to‐the‐pole and the total gradient of the magnetic potential with vertical magnetization. The proposed method yields accurate magnetization directions in synthetic model examples. The total gradient of the magnetic potential with vertical magnetization is less susceptible to data noise than transforms which are derived from the high‐order magnetic field derivatives or tensors. The estimation results are slightly affected by changes in the source magnetization direction. In a field example in the Weilasito region (North China), the reduction‐to‐the‐pole fields calculated using the estimated magnetization directions are well centred over the source. The proposed method obtained a more focused magnetization direction than that of a three‐dimensional magnetization vector inversion. The total gradient of the magnetic potential with vertical magnetization therefore provides a novel and accurate approach to determine the total magnetization direction from the total field anomaly in a variety of situations.

Asymptotic evolution of speckle patterns to synthesize non-homogeneous string beams

We analyze the evolution of the speckle pattern subjected to a compression showing that the spatial evolution of the probability density function satisfies a non-linear diffusion equation. Its asymptotic solution corresponds to a non-homogeneous wave with string-shape. During the compression, an irradiance interaction is generated between the speckles. The interaction satisfies a type-logistic equation. The electric field components associated with the speckles present a random behavior, however, during the compression process, the transversal components cancel each other, and the resulting light presents a state of polarization parallel to the propagation coordinate, justifying the non-homogeneous behavior. Computer simulations are presented.

UV and IR effects in axion quality control

Motivated by recent discussions and the absence of exact global symmetries in UV completions of gravity we re-examine the axion quality problem (and naturalness issues more generally) using antisymmetric Kalb-Ramond (KR) fields rather than their pseudoscalar duals, as suggested by string and higher dimensional theories. Two types of axions can be identified: a model independent S-type axion dual to a two form Bμν in 4D and a T-type axion coming directly as 4D scalar Kaluza-Klein (KK) components of higher-dimensional tensor fields. For T-type axions our conclusions largely agree with earlier workers for the axion quality problem, but we also reconcile why T-type axions can couple to matter localized on 3-branes with Planck suppressed strength even when the axion decay constants are of order the KK scale. For S-type axions, we review the duality between form fields and massive scalars and show how duality impacts naturalness arguments about the UV sensitivity of the scalar potential. In particular UV contributions on the KR side suppress contributions on the scalar side by powers of m/M with m the axion mass and M the UV scale. We re-examine how the axion quality problem is formulated on the dual side and compare to recent treatments. We study how axion quality is affected by the ubiquity of p-form gauge potentials (for both p = 2 and p = 3) in string vacua and identify two criteria that can potentially lead to a problem. We also show why most fields do not satisfy these criteria, but when they do the existence of multiple fields also provides mechanisms for resolving it. We conclude that the quality problem is easily evaded.

Isotachophoresis with Oscillating Sample Zones to Control the Spatial Overlap of Co-focused Species.

Microfluidic isotachophoresis (ITP) is a powerful technique that can significantly increase the reaction rate of homogeneous chemical reactions by cofocusing reactants in a narrow sample zone. Correspondingly, ITP has been utilized to reduce the reaction time in various bioanalytical assays. However, in conventional ITP, it is hardly possible to control the reaction rate in real time, i.e., speeding up or slowing down a reaction on demand. Here, we experimentally demonstrate a new mode of ITP that allows the spatial overlap of two ITP zones to be precisely controlled over time, which is a crucial first step toward controlling reaction rates. Two nonreactive samples are initially focused and separated by a spacer using a DC electric field. By superimposing an oscillating field component with sufficiently high amplitude on the DC field, the spatial overlap of their concentration profiles is temporarily increased due to electromigration dispersion. The time-average of this overlap can be precisely controlled by varying the frequency and amplitude of the oscillation. We suggest that this scheme can be transferred to chemical reactions between ionic species with sufficiently different electrophoretic mobilities. Tuning the parameters of the oscillatory electric field should allow direct control of the corresponding reaction rate.

An identification algorithm of lateral correction amount for the weeding components in paddy fields based on multi-sensor fusion

In this paper, an identification algorithm of lateral correction amount for the weeding components in paddy fields based on multi-sensor fusion is proposed, which can accurately obtain the lateral deviation between the weeding components and the seedling rows under different soil hardness in paddy fields to avoid crushing seedlings. The proposed method first fuses the RGB images with depth images to obtain the three-dimensional point cloud of seedlings, establishes a visual calibration system to calibrate the positions of the weeding component at the limit positions in the camera coordinate system, then obtains the relative pose relationship between the camera coordinate system and the ground coordinate system based on the inertial measurement unit to solve the influence of the altitude change of the camera on the identification of the lateral correction amount, and finally calculates the lateral correction amount based on the lateral deviation model in the ground coordinate system. The experimental platforms for the visual calibration of the weeding components and the identification of the lateral correction amount were established. The experimental results showed that the mean positioning error of the weeding components was 2.766 mm, the mean identification error of the lateral correction amount did not exceed 0.22 cm, and the standard deviation of the identification error did not exceed 0.18 cm.

Realizing the diffraction coupling of silver nanodisk pair array for high-quality sensing

We report a novel approach to enhance the local electromagnetic fields of silver nanodisk pair arrays to achieve high-quality sensing. It is found that through lifting metallic nanodisk pair array by dielectric nanopillars to decrease the effects of substrates, the strong diffraction coupling of metallic nanodisk pair array can be achieved, which will result in a mixed localized surface plasmon resonance (LSPR) with huge electric field enhancement. More importantly, we also demonstrate that for such a diffraction coupling, the electric field component of the lattice resonance mode of periodic arrays must be parallel to the induced electric moment in the silver nanodisk pair array. Due to ultra-narrow linewidth and great electric field enhancement at the LSPR, the metallic nanodisk pair array performs high sensitivity (S = 760 nm RIU−1, S* = 89.5 RIU−1) and figure of merit (FOM = 492, FOM* = 6147), which holds important applications in high-efficiency biomedical sensing.

Adaptive ultrasonic full-matrix imaging of internal defects in CFRP laminates with arbitrary stacking sequences

The phased-array-based ultrasonic full-matrix imaging of carbon fibre-reinforced polymer (CFRP) laminates with total focusing method (TFM) is promising yet challenging due to the layered configuration and strong anisotropy. Traditionally, the precise a priori knowledge of ultrasonic ray paths in anisotropic CFRP laminates are required for accurate TFM imaging, making the inspection process complicated and time consuming. In this work, an adaptive ultrasonic-imaging method is proposed for arbitrarily anisotropic CFRP laminates through full-matrix capture (FMC) and TFM. Firstly, the elastic constants are derived from the FMC data, upon which the 3D group-velocity profiles of ultrasonic waves in CFRP laminates with arbitrary stacking sequences can be calculated. The anisotropic effect is then adaptively corrected for TFM. To verify the effectiveness of proposed method, simulations and experiments are conducted on different anisotropic CFRP laminates with mimicked defects, such as delamination, cracks, voids, etc. The simulated and experimental results well agree with each other, indicating that the proposed method can accurately reconstruct the internal defects of different types. This work provides a convenient and comprehensive avenue towards the ultrasonic inspection of arbitrarily anisotropic CFRP laminates, which markedly benefit the quality control of CFRP components in various fields.

Evaluation of dB/dt amplitudes and sources over the Brazilian region during geomagnetic storms in the 2021–2022 biennium

The rate of change of the geomagnetic field (dB/dt) observed at Earth’s surface has been used as a proxy of geomagnetically induced currents, which are known to be hazardous for grounded technological systems such as high-voltage power grid systems. The dB/dt rates have been well characterized in the high latitude region (≳60°), but much less information is available for the low latitudes to date. To overcome this limitation, we have examined dB/dt rates on the H component of the geomagnetic field as measured by an array of stations operated by the EMBRACE Magnetometer Network in Brazil. The main focus is to characterize dB/dt occurrence at very low latitudes (≲22°) of the Brazilian peculiar territory, whose magnetic measurements are influenced by the equatorial electrojet and the presence of the South Atlantic Magnetic Anomaly (SAMA). The period investigated is from 2021 to 2022, over the ascending phase of the solar cycle 25. The statistical analysis demonstrates that dB/dt peak magnitudes are generally below 0.5 nT/s during magnetic storms, and exhibit a dependence on the solar cycle for the station near the center of the SAMA. However, we obtain for a particular case in 2021 that dB/dt reached 1.35 nT/s in magnitude at the magnetic equator during daytime, which is a significant value even for higher latitudes. A case study of the induced geoelectric fields during this event shows that the conductivity structure beneath two compared sites plays a major role in the amplitude of such fields than dB/dt amplitude. Also, the MLT distributions of dB/dt indicate that ultra-low frequency waves can be a major source of these signals in lower latitudes.

Polarization properties of E-FISH signals and optimization of simultaneous measurement of electric field vectors

Electric field measurements based on the electric field induced second harmonic (E-FISH) method have been employed in a wide range of studies. Most studies typically measure two components of the electric field separately. Although there have been proposals for the simultaneous measurement of electric field vectors, the imbalance of the two corresponding E-FISH signals has limited its application. Furthermore, the relationship between the polarization of the E-FISH signal and the direction of external electric field remains unclear. In this paper, the general expressions for the polarization and power of both components of E-FISH signals are derived, assuming arbitrary probe beam polarization and external electric field direction. The theoretical results indicate that the polarization of E-FISH signals varies along the interaction length. The final signal’s polarization is elliptically polarized for arbitrary electric field distribution and is correlated with the polarization of the probe beam, which deviates from what is commonly assumed to be consistent with the external electric field. If the polarization of the probe beam is not parallel to the axes, the power of each signal component is determined by both components of the external electric field, which lays the foundation for the simultaneous measurement of electric field vectors. This theoretical prediction is subsequently validated by experimental results. Finally, the power maps suggest that the optimal polarization angle of the probe beam is 45° or 135° to achieve a balanced signal power when measuring an unknown electric field vector. Both components of the electric field can be simultaneously obtained according to the theoretical relationship.

Testing pulsation diagnostics in the rapidly oscillating magnetic Ap star γ Equ using near-infrared CRIRES+ observations

Context. Pulsations of rapidly oscillating Ap stars and their interaction with the stellar magnetic field have not been studied in the near-infrared (near-IR) region despite the benefits these observations offer compared to visual wavelengths. The main advantage of the near-IR is the quadratic dependence of the Zeeman effect on the wavelength, as opposed to the linear dependence of the Doppler effect. Aims. To test pulsation diagnostics of roAp stars in the near-IR, we aim to investigate the pulsation behaviour of one of the brightest magnetic roAp stars, γ Equ, which possesses a strong surface magnetic field of the order of several kilogauss and exhibits magnetically split spectral lines in its spectra. Methods. Two magnetically split spectral lines belonging to different elements, the triplet Fe I at 1563.63 nm and the pseudo-doublet Ce III at 1629.2 nm, were recorded with CRIRES+ over about one hour in the H band with the aim of understanding the character of the line profile variability and the pulsation behaviour of the magnetic field modulus. Results. The profile shapes of both studied magnetically split spectral lines vary in a rather complex manner probably due to a significant decrease in the strength of the longitudinal field component and an increase in the strength of the transverse field components over the last decade. A mean magnetic field modulus of 3.9 kG was determined for the Zeeman triplet Fe I at 1563.63 nm, whereas for the pseudo-doublet Ce III at 1629.2 nm we observe a much lower value of only about 2.9 kG. For comparison, a mean field modulus of 3.4kG was determined using the Zeeman doublet Fe II at 6249.25 in optical PEPSI spectra recorded just about two weeks before the CRIRES+ observations. Different effects that may lead to the differences in the field modulus values are discussed. Our measurements of the mean magnetic field modulus using the line profiles recorded in different pulsational phase bins suggest a field modulus variability of 32 G for the Zeeman triplet Fe I at 1563.63 nm and 102 G for the pseudo-doublet Ce III at 1629.2 nm.

In Situ Observations at the Air‐Sea Interface by Expendable Air‐Deployed Drifters Under Hurricane Michael (2018)

AbstractAn array of surface drifters deployed ahead of Hurricane Michael measured the surface temperature, pressure, directional wind and wave spectra, and surface currents one day before it made landfall as a Category 5 Hurricane. The drifters, 25–50 km apart, spanned two counter‐rotating ocean eddies as Hurricane Michael rapidly intensified. The drifters measured the shift of wave energy between frequency bands in each quadrant of the storm, the response of upper ocean currents, and the resulting cold wake following Michael's passage. Wave energy was greatest in the front quadrants and rapidly decreased in the left‐rear quadrant, where wind and wave energy were misaligned, and components of the wave field were aligned with currents. Hurricane Michael's wave field agreed with previous studies of nondirectional wave spectra across multiple tropical cyclones but had some unique characteristics. The analysis demonstrates how co‐located surface wind and wave observations can complement existing airborne and satellite observations.