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Helioseismic inversions reveal a major discrepancy in sound speed between the Sun and the standard solar model just below the base of solar convection zone. We demonstrate that this discrepancy is caused by the inherent shortcomings of the…

太阳与恒星天体物理 · 物理学 2012-10-17 Chunguang Zhang , Licai Deng , Darun Xiong , Jørgen Christensen-Dalsgaard

Stokes inversion codes are crucial in returning properties of the solar atmosphere, such as temperature and magnetic field strength. However, the success of such algorithms to return reliable values can be hindered by the presence of…

太阳与恒星天体物理 · 物理学 2021-01-20 P. H. Keys , O. Steiner , G. Vigeesh

Mapping the large-scale subsurface plasma flow profile within the Sun has been attempted using various methods for several decades. One such flow in particular is the meridional circulation, for which numerous studies have been published.…

太阳与恒星天体物理 · 物理学 2023-08-23 Aleczander Herczeg , Jason Jackiewicz

The Helioseismic and Magnetic Imager (HMI) onboard NASA's Solar Dynamics Observatory (SDO) produces estimates of the photospheric magnetic field which are a critical input to many space weather modelling and forecasting systems. The…

In time-distance helioseismology, the time signals (Doppler shifts) at two points on the solar surface, separated by a fixed angular distance are cross-correlated, and this leads to a wave packet signal. Accurately measuring the travel…

天体物理学 · 物理学 2011-02-11 R. Nigam , A. G. Kosovichev , P. H. Scherrer

This paper investigates the problem of time-harmonic acoustic scattering in an inhomogeneous medium with a complex topological structure. Specifically, the medium is anisotropic and contains several disjoint sound-soft obstacles. This model…

数学物理 · 物理学 2025-09-30 Huaian Diao , Qingle Meng , Zhiying Sun

Helioseismic signatures of dynamo waves have recently been discovered in variations of the solar differential rotation, offering valuable insights into the type of dynamo mechanism operating in the solar convection zone. To characterize…

太阳与恒星天体物理 · 物理学 2025-05-19 Krishnendu Mandal , Alexander G. Kosovichev , Valery V. Pipin , Sylvain G. Korzennik

The purpose of deep-focusing time--distance helioseismology is to construct seismic measurements that have a high sensitivity to the physical conditions at a desired target point in the solar interior. With this technique, pairs of points…

太阳与恒星天体物理 · 物理学 2018-04-09 Majid Pourabdian , Damien Fournier , Laurent Gizon

A major goal of helioseismology is the three-dimensional reconstruction of the three velocity components of convective flows in the solar interior from sets of wave travel-time measurements. For small amplitude flows, the forward problem is…

数值分析 · 数学 2017-03-28 D. Fournier , L. Gizon , M. Holzke , T. Hohage

The Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI) filtergrams, taken at six wavelengths around the Fe I 6173.3 {\AA} line, contain information about the line-of-sight velocity over a range of heights in the solar…

We demonstrate a computational inverse design method for optimizing broadband-absorbing metasurfaces made of arbitrary dispersive media. Our figure of merit is the time-averaged instantaneous power dissipation in a single unit cell within a…

Modeling metasurfaces with high accuracy and efficiency is challenging because they have features smaller than the wavelength but sizes much larger than the wavelength. Full wave simulation is accurate but very slow. Popular design…

光学 · 物理学 2023-04-04 Zhicheng Wu , Xiaoyan Huang , Nanfang Yu , Zongfu Yu

We derive expectations for signatures in the measured travel times of waves that interact with thermal anomalies and jets. A series of numerical experiments that involve the dynamic linear evolution of an acoustic wave field in a solar-like…

天体物理学 · 物理学 2011-02-11 Shravan M. Hanasoge , Thomas L. Duvall

Existing time-resolved non-line-of-sight (NLOS) imaging methods reconstruct hidden scenes by inverting the optical paths of indirect illumination measured at visible relay surfaces. These methods are prone to reconstruction artifacts due to…

计算机视觉与模式识别 · 计算机科学 2023-09-27 Kiseok Choi , Inchul Kim , Dongyoung Choi , Julio Marco , Diego Gutierrez , Min H. Kim

Wavelength division multiplexers are fundamental to the functioning and performance of integrated photonic circuits, with applications ranging from optical interconnects to sensing and quantum technologies. Current solutions are limited by…

光学 · 物理学 2026-03-11 Sydney Mason , Geun Ho Ahn , Jakob Grzesik , Sungjun Eun , Jelena Vučković

The spatial-temporal distribution of underwater sound velocity affects the propagation mode of underwater acoustic signals. Therefore, rapid estimation and prediction of underwater sound velocity distribution is crucial for providing…

声音 · 计算机科学 2025-03-31 Jiajun Lu , Hao Zhang , Pengfei Wu , Sijia Li , Wei Huang

One-dimensional convolution is a widely used deep learning technique in prestack amplitude variation with offset (AVO) inversion; however, it lacks lateral continuity. Although two-dimensional convolution improves lateral continuity, due to…

地球物理 · 物理学 2025-03-19 Yingtian Liu , Yong Li , Junheng Peng , Mingwei Wang

We describe a novel framework for estimating subsurface properties, such as rock permeability and porosity, from time-lapse observed seismic data by coupling full-waveform inversion, subsurface flow processes, and rock physics models. For…

地球物理 · 物理学 2020-05-06 Dongzhuo Li , Kailai Xu , Jerry M. Harris , Eric Darve

Multi-source localization is an important and challenging technique for multi-talker conversation analysis. This paper proposes a novel supervised learning method using deep neural networks to estimate the direction of arrival (DOA) of all…

音频与语音处理 · 电气工程与系统科学 2021-11-30 Aswin Shanmugam Subramanian , Chao Weng , Shinji Watanabe , Meng Yu , Dong Yu

This paper introduces a 3D point cloud sequence learning model based on inconsistent spatio-temporal propagation for LiDAR odometry, termed DSLO. It consists of a pyramid structure with a spatial information reuse strategy, a sequential…

计算机视觉与模式识别 · 计算机科学 2024-09-04 Huixin Zhang , Guangming Wang , Xinrui Wu , Chenfeng Xu , Mingyu Ding , Masayoshi Tomizuka , Wei Zhan , Hesheng Wang