Higher Wavenumbers Research Articles

Instabilities of rotating inclined buoyancy layers.

The boundary layer near a cooled inclined plate, which is immersed in a stably stratified fluid rotating about an axis parallel to the direction of gravity, is a model for katabatic flows at high latitudes. In this paper the base flow of such an inclined buoyancy layer is solved analytically for arbitrary Prandtl numbers. By applying linear stability analyses, five unstable modes are identified for both the fixed temperature and the isoflux boundary conditions, i.e., the stationary longitudinal roll (LR) mode, the oblique roll with low streamwise wave-number (OR-1) and high streamwise wave-number (OR-2) modes, and the Tolmien-Schlichting (TS) wave with low streamwise wave-number (TS-1) and high streamwise wave-number (TS-2) modes. It is indicated that the Coriolis effect induced by the rotation leads the critical modes to be three dimensional, and a larger tilt angle of the plate and stronger Coriolis effect cause both TS wave modes to be more unstable for both thermal boundary conditions. When the Coriolis effect is considered, the OR-1 and OR-2 modes are the most unstable mode at low and high tilt angles, respectively, but the TS-1 wave mode may be the most unstable one when the plate is nearly vertical. In addition, the spanwise phase velocities of the TS wave modes change directions as the tilt angle passes some threshold values for both thermal boundary conditions except for the TS-1 wave mode with a fixed temperature boundary condition, which propagates in the same spanwise direction for all explored tilt angles.

Comparative study of TiO2–Fe3O4 photocatalysts synthesized by conventional and microwave methods for metronidazole removal

This study focused on a direct comparison of conventional hydrothermal and microwave treatment during the synthesis of TiO2–Fe3O4 photocatalyst, which is an effective catalyst for decomposing metronidazole. The photocatalyst underwent various characterization analyses, including X-ray diffraction, Raman spectroscopy, transmission electron microscopy, energy dispersive X-ray, and diffuse reflectance spectroscopy. The Raman spectroscopy analysis revealed that the materials obtained through the conventional hydrothermal treatment consisted of separate phases of anatase and magnetite. On the other hand, the materials synthesized using the microwave process showed a noticeable shift in the Eg band (143 cm−1) and its half-width towards higher wavenumbers. This shift is likely due to the introduction of Fe ions into the TiO2 lattice. Additionally, both conventional hydrothermal and microwave synthesis routes produced TiO2–Fe3O4 systems with superparamagnetic properties, as demonstrated by SQUID magnetic measurements. The TEM analysis revealed that the materials synthesized using the microwave process exhibited higher homogeneity, with no noticeable large aggregates observed. Finally, this work proposed a convenient LED photoreactor that effectively utilized the photo-oxidative properties of TiO2–Fe3O4 photocatalysts to remove metronidazole. Combining photoactive TiO2–Fe3O4 catalysts with an energy-efficient LED reactor resulted in a low electrical energy per order (EEO).

Inferring the impact of feedback on the matter distribution using the Sunyaev Zel’dovich effect: insights from CAMELS simulations and ACT + DES data

ABSTRACT Feedback from active galactic nuclei and stellar processes changes the matter distribution on small scales, leading to significant systematic uncertainty in weak lensing constraints on cosmology. We investigate how the observable properties of group-scale haloes can constrain feedback’s impact on the matter distribution using Cosmology and Astrophysics with MachinE Learning Simulations (CAMELS). Extending the results of previous work to smaller halo masses and higher wavenumber, k, we find that the baryon fraction in haloes contains significant information about the impact of feedback on the matter power spectrum. We explore how the thermal Sunyaev Zel’dovich (tSZ) signal from group-scale haloes contains similar information. Using recent Dark Energy Survey weak lensing and Atacama Cosmology Telescope tSZ cross-correlation measurements and models trained on CAMELS, we obtain 10 per cent constraints on feedback effects on the power spectrum at $k \sim 5\, h\, {\rm Mpc}^{-1}$. We show that with future surveys, it will be possible to constrain baryonic effects on the power spectrum to $\mathcal {O}(\lt 1~{{\ \rm per\ cent}})$ at $k = 1\, h\, {\rm Mpc}^{-1}$ and $\mathcal {O}(3~{{\ \rm per\ cent}})$ at $k = 5\, h\, {\rm Mpc}^{-1}$ using the methods that we introduce here. Finally, we investigate the impact of feedback on the matter bispectrum, finding that tSZ observables are highly informative in this case.

A variegated effective elastic modulus in metabeams under periodically distributed loads

A class of beam-like lattice structures, or metabeams under static, sinusoidally distributed transverse loads is discussed. Their neutral axis deflects either in-phase, out-of-phase or shows no deflection, depending on the beam design parameters, and also on the spatial frequency of the static load. These outcomes contrast the behavior of continuum beams, deflecting always in-phase with the load, and they are interpreted on the basis of a positive, negative and near-infinite effective Young's modulus of the structured beams in bending. They also represent a collective effect of the behavior of multiple elements in the lattice that cannot be realized from the performance of an isolated unit cell. A long-range periodic order and nonlocality of the lattice interaction is essential for this unusual behaviors, and those are particularly pronounced at higher wavenumbers, when the load wavelength becomes comparable with the range of direct interactions in the lattice. Theoretical discussion and predictions agree well with numerical experiments performed on the basis of commonly accepted models. Practical applications could be found in advanced reinforcing materials for building foundations, deformation mitigation for lightweight structures and bridges, and in smart mechanical systems able to differentiate external stimuli and to respond selectively.

Enhancement of protein detection on cultural heritage samples after SYPRO™ Ruby staining by optical microscopy and micro-FTIR spectroscopy

The paper investigates SYPRO™ Ruby staining in combination with external reflection micro-FTIR spectroscopy, for the detection of proteinaceous media in paint layers on cultural heritage, from unembedded micro-fragments and samples embedded in cross-sections. Combining FTIR spectroscopy with staining helped to verify that the FTIR mapping is accurate when performed by the integration of the main amide I and II bands, despite their naturally occurrent distortions due to the specular component and material absorption/surface properties. The research filled some gaps in the published literature on SYPRO™ Ruby interaction with different Cultural Heritage materials, including identifying drawbacks, e.g. swelling mechanisms in the sample after staining. The effects of the staining were investigated on different reference samples containing rabbit skin glue (proteinaceous), and samples from cultural heritage case studies undergoing technical examination as part of research projects, where identification of protein is an important aspect of understanding the sequence of complex multi-layers within a sample. Results showed that, when external reflection µ-FTIR is performed after the staining, the contribution from amide I and II, which occurs at higher wavenumbers than in transmission or attenuated total reflection, is more resolved and therefore easier to determine. When inorganic or organic compounds are present in the same layer, variation in the position of amide bands can occur. However, they can be used for chemical mapping using simple data-treatment strategies, as validated with the positive staining. This type of data processing gives a good estimation of the protein distribution in the layers, both in terms of morphology and thickness, on mock-up samples and cross-sections from real case studies.

Electrochemical Surface-Enhanced Raman Spectroscopy for Aniline Adsorbed on Silver Electrodes: A DFT Study of the Anharmonic Effects of Amino Wagging Vibrational Modes

Aniline molecules exhibit a special amino wagging vibrational mode on the surface of the silver electrode. The corresponding Raman peak not only displays enhanced Raman signals in surface-enhanced Raman spectroscopy (SERS) experiments but also shows a shift toward higher wavenumbers. This work adopts a molecule-metal cluster model to investigate the normal Raman spectra of aniline molecules and their SERS spectra adsorbed on silver electrode surfaces by density functional theory (DFT) approaches. Based on the harmonic approximation, the influence of anharmonic effects on the normal Raman and SERS spectra of aniline is further considered. Our calculated results of the anharmonic Raman spectra of free aniline molecules show that their anharmonic effect mainly comes from the amino wagging vibrational mode. Then, the anharmonic Raman spectra of aniline binding to neutral and positively charged silver clusters were calculated and compared with the harmonic Raman spectra. It was found that the coupling effect between vibrational modes also greatly affects the Raman spectral characteristics. Finally, the excited state energy gap and pre-resonance Raman spectra of the aniline–silver cluster complexes are studied, and it is believed that there may be a charge-transfer enhancement mechanism.

The effect of side walls on the stability of falling films

We study the influence of side walls on the stability of falling liquid films. We combine a temporal biglobal stability analysis based on the linearised Navier–Stokes equations with experiments measuring the spatial growth rate of sinusoidal waves flowing downstream an inclined channel. Very good agreement was found when comparing the theoretical and experimental results. Strong lateral confinement of the channel stabilises the flow. In the wavenumber-Reynolds number space, the instability region experiences a fragmentation due to selective damping of moderate wavenumbers. For this range of parameters, the three-dimensional confined problem shows several prominent stability modes which are classified into two categories, the well-known Kapitza hydrodynamic instability mode (H-mode) and a new unstable mode, we refer to it as wall-mode (W-mode). The two mode types are stabilised differently, where the H-modes are stabilised at small wavenumbers, while the W-modes experience stabilisation at high wavenumbers, and at sufficiently small channel widths, only the W-mode is observed. The reason behind the unique H-modes stabilisation is that they become analogous to waveguide modes, which can not propagate below a certain cut-off wavenumber. The spatial structure of the eigenmodes experiences significant restructuring at wavenumbers smaller than the most damped wavenumber. The mode switching preserves the spatial symmetry of the unstable mode.

Aluminum and Zinc Co-substituted Cobalt Ferrite: Structural, Magnetic, and Magnetostrictive Properties

We report on the influence of Al and Zn co-substitution on the structural, magnetic, and magnetostrictive properties of cobalt ferrite (Co1–xZnxFe2–xAlxO4, 0 ≤ x ≤ 0.15; CZFAO) materials, which were made using a glycine-nitrate autocombustion process. The cubic spinel structure is present in both the as-synthesized and the sintered CZFAO samples, where it was evident that the crystallite size and lattice parameter reduced with increasing x due to the incorporation of smaller Al3+ ions in place of larger Fe3+ ions in spinel ferrite. Co-substitution induced changes in the metal–oxygen bond lengths, causing both the tetrahedral and octahedral infrared and Raman spectroscopic bands to shift toward higher wavenumbers. The electron microscopy analyses indicate that the Al–Zn substitution induces grain growth, leading to a dense, interconnected grain morphology. Mossbauer analyses indicate that the Al3+ occupies the octahedral site, whereas Zn2+ is substituted at the tetrahedral site. Due to equal magnetic dilution of both tetrahedral and octahedral sites caused by the presence of Zn and Al at the appropriate sites, the saturation magnetization MS of CZFAO is the same as that of pure CFO. All other magnetic parameters (coercivity HC, magnetocrystalline anisotropy constant K1, and Curie temperature TC) decrease with increasing x, where the decline observed is mostly due to superexchange interaction (A-O-B) reduction caused by the substituents’ non-magnetic character. CZFAO materials exhibit higher magnetostriction strain λ and strain sensitivity dλ/dH at relatively low magnetic fields; among all the samples, x = 0.15 demonstrates a maximum strain sensitivity of −2.53 × 10–9 m/A at 23 kA/m magnetic field. The composition-tuned CZFAO materials with desirable properties are suitable for application in torque sensors.

Cost of Transport of Undulating Fin Propulsion.

Autonomous robots are used to inspect, repair and maintain underwater assets. These tasks require energy-efficient robots, including efficient movement to extend available operational time. To examine the suitability of a propulsion system based on undulating fins, we built two robots with one and two fins, respectively, and conducted a parametric study for combinations of frequency, amplitude, wavenumber and fin shapes in free-swimming experiments, measuring steady-state swimming speed, power consumption and cost of transport. The following trends emerged for both robots. Swimming speed was more strongly affected by frequency than amplitude across the examined wavenumbers and fin heights. Power consumption was sensitive to frequency at low wavenumbers, and increasingly sensitive to amplitude at high wavenumbers. This increasing sensitivity of amplitude was more pronounced in tall rather than short fins. Cost of transport showed a complex relation with fin size and kinematics and changed drastically across the mapped parameter space. At equal fin kinematics as the single-finned robot, the double-finned robot swam slightly faster (>10%) with slightly lower power consumption (<20%) and cost of transport (<40%). Overall, the robots perform similarly to finned biological swimmers and other bio-inspired robots, but do not outperform robots with conventional propulsion systems.

A systematic study of rare‐earth ions size‐dependent structural phase transition from monazite to zircon‐type in rare earth chromates using Raman spectroscopy

AbstractRare earth chromates (RCrO4) undergo monazite to zircon‐type structural phase transition due to a decreased rare‐earth ion size. They also exhibit an intermediate mixed phase. However, there is no systematic study on the influence of structural distortion on their phononic behavior, which is quite sensitive to subtle environmental variations. A change in the room temperature phononic spectrum was studied in the family of RCrO4 compounds, where R was varied from La to Yb using Raman modes. With an increase in the atomic number from Nd to Yb for zircon‐type phases, the external translational and rotational modes were observed to shift towards lower and higher wavenumbers, respectively. At the same time, all internal vibrational modes shifted towards higher phonon energies. A comparison between Raman modes for monazite, intermediate, and zircon‐type RCrO4 phases showed a gradual shift in the internal modes towards a higher wavenumber. The confirmation of the change in Raman modes with the decreasing radius was found by comparing the rare‐earth elements in DyCrO4 and LaCrO4 with non‐rare‐earth elements in YCrO4.

Spectrum of collective excitations of a quantum fluid of polaritons

We use a recently developed high-resolution coherent probe spectroscopy method to investigate the dispersion of collective excitations of a polaritonic quantum fluid. We measure the dispersion relation with high energy and wavenumber resolution, which allows us to determine the speed of sound in the fluid and to evidence the contribution of an excitonic reservoir. We report on the generation of collective excitations at negative energies, on the ghost branch of the dispersion curve. Precursors of dynamical instabilities are also identified. Our methods open the way to the precise study of quantum hydrodynamics of quantum fluids of light.

Assessing passive scalar dynamics in bubble-induced turbulence using direct numerical simulations

By using direct numerical simulations (DNS) of bubbly flows with passive scalars, we show a transition in the scalar spectra from a $k^{-5/3}$ to a $k^{-3}$ scaling with the wavenumber $k$ , in contrast with those of single-phase isotropic turbulence. For cases with a mean scalar gradient in the horizontal direction, the scalar spectrum decays faster than $k^{-3}$ at high wavenumbers. While the $k^{-3}$ scaling is well established in the bubbly flow velocity spectrum, the scalar spectrum behaviour is not fully understood. We find that the transition length scale of the scalar spectra is comparable to or below the bubble diameter and decreases with the molecular diffusivity of the scalar in the liquid. We use DNS to compute the scalar spectrum budget and show that the scalar fluctuations are produced by the mean scalar gradient at length scales above the bubble diameter, contrary to the velocity fluctuations. At length scales below the bubble diameter, the net scalar transfer scales as $k^{-1}$ inducing the $k^{-3}$ scaling of the scalar spectra. This finding is consistent with the hypothesis proposed by Dung et al. (J. Fluid Mech., vol. 958, 2023, p. A5) about the physical mechanism behind the $k^{-3}$ scaling. We also show dependencies of the bubble suspension's convective scalar diffusivity on the gas volume fraction and molecular diffusivity that differ based on the direction of the mean scalar gradient. For a mean scalar gradient in the vertical direction, we find and qualitatively explain a significant effect of the molecular diffusivity in the gas on the convective scalar diffusivity.

The effect of low temperature on the Raman spectra of calcium-rich sulfates on Mars

Abstract Raman spectra (532 nm diode laser) of gypsum, syngenite and görgeyite powders were studied from 273 to 83 K every −10 K. Although it was found that not all the Raman peaks are temperature-sensitive, the effect of temperature on the Raman signal of some bands was modelled. It was observed that the main bands of the three sulfates shift toward higher wavenumbers as temperature decreases. The strengthening of the bonds causes an increase in energy and, consequently, higher wavenumbers. However, –OH bands shift depending on the crystal structure they acquire as the temperature decreases, so not all –OH bands behave in the same way. Finally, the gypsum –OH bands change to more ordered crystalline structures with decreasing temperature, so their bandwidths become narrower and sharper.

Determination of anisotropic optical properties of MOCVD grown m-plane α-(Al x Ga1−x )2O3 alloys

The anisotropic dielectric functions (DF) of corundum structured m-plane α-(Al x Ga1−x )2O3 thin films (up to x = 0.76) grown on m-plane sapphire substrate by metalorganic CVD have been investigated. IR and visible–UV spectroscopic ellipsometry yields the DFs, while X-ray diffraction revealed the lattice parameters (a, m, c), showing the samples are almost fully relaxed. Analysis of the IR DFs from 250 to 6000 cm−1 by a complex Lorentz oscillator model yields the anisotropic IR active phonons E u and A 2u and the shift towards higher wavenumbers with increasing Al content. Analyzing the UV DFs from 0.5 to 6.6 eV we find the change in the dielectric limits ε ∞ and the shift of the Γ-point transition energies with increasing Al content. This results in anisotropic bowing parameters for α-(Al x Ga1−x )2O3 of b ⊥ = 2.1 eV and b ∣∣ = 1.7 eV.

Improved potential-energy and dipole-moment functions of the ground electronic state of phosphorus nitride

Ab initio calculations of the PN potential and electric dipole moment in the X1Σ+ ground electronic state were performed at short bond lengths, r=0.2–0.8 Å, and semi-empirical analytical potential-energy and dipole-moment functions were constructed based on all available experimental and theoretical information. The analytical forms for the potential-energy functions include the Extended Morse Oscillator and the Extended Hulburt-Hirshfelder potential. The dipole-moment function of PN was presented by our irregular and rational functions previously used for CO. The potential-energy and dipole-moment model functions were fitted simultaneously to the experimental line positions and permanent dipoles at v=0-2, as well as to the ab initio data from our present and previous studies. With these new functions, the improved line list for the ground electronic state of 31P14N was calculated. We show that the new analytic representations of the potential and dipole moment functions help significantly reduce the numerical noise in the intensities of high overtones as well as the associated saturation at high wavenumbers leading to the so-called “overtone plateaus” in spectra of diatomic molecules (see Medvedev et al., J. Mol. Spectrosc., 330, 36 (2016)) and thus provide reliable transition intensities at very high transition frequencies. The 3-0 band is identified as vibrational anomaly, and rotational anomalies inside this and some other bands are found.

Label-Free Cytometric Evaluation of Mitosis via Stimulated Raman Scattering Microscopy and Spectral Phasor Analysis.

Hyperspectral stimulated Raman scattering (SRS) microscopy is a robust imaging tool for the analysis of biological systems. Here, we present a unique perspective, a label-free spatiotemporal map of mitosis, by integrating hyperspectral SRS microscopy with advanced chemometrics to assess the intrinsic biomolecular properties of an essential process of mammalian life. The application of spectral phasor analysis to multiwavelength SRS images in the high-wavenumber (HWN) region of the Raman spectrum enabled the segmentation of subcellular organelles based on innate SRS spectra. Traditional imaging of DNA is primarily reliant on using fluorescent probes or stains which can affect the biophysical properties of the cell. Here, we demonstrate the label-free visualization of nuclear dynamics during mitosis coupled with an evaluation of its spectral profile in a rapid and reproducible manner. These results provide a snapshot of the cell division cycle and chemical variability between intracellular compartments in single-cell models, which is central to understanding the molecular foundations of these fundamental biological processes. The evaluation of HWN images by phasor analysis also facilitated the differentiation between cells in separate phases of the cell cycle based solely on their nuclear SRS spectral signal, which offers an interesting label-free approach in combination with flow cytometry. Therefore, this study demonstrates that SRS microscopy combined with spectral phasor analysis is a valuable method for detailed optical fingerprinting at the subcellular level.

3D hydrodynamics simulations of internal gravity waves in red giant branch stars

ABSTRACT We present the first 3D hydrodynamics simulations of the excitation and propagation of internal gravity waves (IGWs) in the radiative interiors of low-mass stars on the red giant branch (RGB). We use the ppmstar explicit gas dynamics code to simulate a portion of the convective envelope and all the radiative zone down to the hydrogen-burning shell of a $1.2\, {\rm M}_{\odot }$ upper RGB star. We perform simulations for different grid resolutions (7683, 15363, and 28803), a range of driving luminosities, and two different stratifications (corresponding to the bump luminosity and the tip of the RGB). Our RGB tip simulations can be directly performed at the nominal luminosity, circumventing the need for extrapolations to lower luminosities. A rich, continuous spectrum of IGWs is observed, with a significant amount of total power contained at high wavenumbers. By following the time evolution of a passive dye in the stable layers, we find that IGW mixing in our simulations is weaker than predicted by a simple analytical prescription based on shear mixing and not efficient enough to explain the missing RGB extra mixing. However, we may be underestimating the efficiency of IGW mixing given that our simulations include a limited portion of the convective envelope. Quadrupling its radial extent compared to our fiducial set-up increases convective velocities by up to a factor 2 and IGW velocities by up to a factor 4. We also report the formation of a $\sim 0.2\, H_P$ penetration zone and evidence that IGWs are excited by plumes that overshoot into the stable layers.

Upscale transfer of waves in one-dimensional rotating shallow water

We study the inverse flux of waves in one of the simplest geophysical fluid dynamics models: one-dimensional rotating shallow water equations. Based on direct numerical integration of the governing equations, we find that waves injected at small scales get transferred upscale predominantly via resonant quartic interactions between wave modes. The waves’ upscale transfer is non-local and involves turbulent transfer between disparate scales of the flow. Our analysis reveals that the upscale transfer of waves is extremely intermittent and is a result of localized-in-time bursts in wave action flux. These intermittent events of flux bursts lead to shallower waves’ spectrum and relatively higher amplitude wave fields in physical space. On examining statistics of the flow fields, we find that low-energy high wavenumbers more or less comply with the assumptions used in wave turbulence theory, such as uniformly distributed wave phases and the Gaussian distribution of fields, while non-uniform distribution of wave phases and non-Gaussian statistics dominate at large scales or low wavenumbers that contain a major share of the flow energy. Our findings point out that the one-dimensional rotating shallow water equations, despite being a simple geophysical fluid dynamic model, harbour complex and intricate features associated with the upscale transfer of waves that have not been recognized in the past.

Optimal Raman-scattering signal for estimating the Fe3+ content on the clinozoisite–epidote join

Abstract. To provide a tool for fast estimation of the Fe3+ content in Ca2(Al, Fe3+)3Si3O12(OH) epidote grains, including in thin sections and crude-rock samples, we applied Raman spectroscopy to 33 areas from 15 natural samples with Fe3+ ranging from 0.22 to 1.13 atoms per formula unit (apfu), the chemistry of which was independently determined by wavelength-dispersive electron microprobe analysis (WD-EPMA). The Raman spectra were collected from the very areas subjected to WD-EPMA. We have analysed both the OH-stretching region (3215–3615 cm−1) and the spectral range generated by the framework vibrations (15–1215 cm−1). Similarly to the IR spectra, the Raman peaks in the OH-stretching region shift toward higher wavenumbers with increasing Fe. However, the quantification of Fe3+ based on OH-stretching Raman peaks can be hindered by the multicomponent overlapping and significant intensity variations with the crystal orientation. Among the Raman signals generated by framework vibrations, the position of four peaks (near 250, 570, 600, and 1090 cm−1) exhibit a steady linear regression with the increase in Fe content (in apfu). However, the peak near 250 cm−1 attributed to MO6 vibrations also depends on the crystal orientation and therefore is not always well resolved, which worsens the accuracy in Fe-content determination based on its position. The peaks near 570, 600, and 1090 cm−1 arise from Si2O7 vibrational modes, and although their intensities also vary with the crystal orientation, all three signals are well resolved in a random orientation. However, among the three Si2O7-related signals, the 570 cm−1 peak is the sharpest (peak width &lt;10 cm−1) and is easily recognized as a separate peak. Hence, we propose to use the position of this peak as a highly reliable parameter to estimate the Fe content, via the linear trend given as ω570=577.1(3)-12.7(4)x, where ω is the wavenumber (cm−1) and x is Fe content (apfu), with accuracy ± 0.04 Fe3+ apfu. The peaks near 600 and 1090 cm−1 may be complementarily used for the Fe estimate, based on the following relations: ω600=611.6(2)-13.8(4)x and ω1090=1098.8(3)-13.5(5)x. Analyses of the effect of Sr as a substitution for Ca and Cr at the octahedral sites indicate that contents of Sr &lt;0.12 apfu do not interfere with the quantification of Fe via the ω570 (x) relation, whereas Cr &gt;0.16 apfu leads to overestimation of Fe; Cr presence can be recognized however by the broadening of the peaks near 95 and 250 cm−1.

A new electromagnetic probe array diagnostic for analyzing electrostatic and magnetic fluctuations in EAST plasmas

A novel electromagnetic probe array (EMPA) diagnostic, which consists of a magnetic probe array and an electrostatic probe array, has recently been developed on EAST. The EMPA is fixed near the first wall at horizontal port P. The magnetic probe array of the EMPA consists of 24 identical magnetic probes, each of them capable of measuring toroidal, poloidal and radial magnetic fluctuations simultaneously, providing additional toroidal magnetic fluctuation measurements compared with the regular magnetic probes on EAST. With a higher sampling rate and self-resonant frequency, the EMPA magnetic probes can provide higher frequency magnetic fluctuation measurements. The magnetic probe array of the EMPA is composed of two parallel layers of magnetic probes with a radial distance of 63 mm, and each layer of magnetic probes is arranged in four poloidal rows and three toroidal columns. The compact arrangement of the EMPA magnetic probe array largely improves the toroidal mode number measurement ability from to and also improves the high poloidal wave number measurement ability of magnetic fluctuations compared with the regular high frequency magnetic probes on EAST. The electrostatic probe array of the EMPA consists of two sets of four-tip probes and a single-tip probe array with three poloidal rows and four toroidal columns. It complements the electrostatic parameter measurements behind the main limiter and near the first wall in EAST. The engineering details of the EMPA diagnostic, including the mechanical system, the electrical system, the acquisition and control system, and the effective area calibration, are presented. The preliminary applications of the EMPA in L-mode and H-mode discharges on EAST have demonstrated that the EMPA works well for providing information on the magnetic and electrostatic fluctuations and can contribute to deeper physical analysis in future EAST experiments.