Stable reduction to the pole at the magnetic equator

نویسندگان

  • Yaoguo Li
  • Douglas W. Oldenburg
چکیده

The solution of reduction to the pole (RTP) of magnetic data in the wavenumber domain faces a long standing difficulty of instability when the observed data are acquired at low magnetic latitudes or at the equator. We develop a solution to this problem that allows stable reconstruction of the RTP field with a high fidelity even at the magnetic equator. The solution is obtained by inverting the Fourier transform of the observed magnetic data in the wavenumber domain with explicit regularization. The degree of regularization is chosen according to the estimated error level in the data. The Fourier transform of the RTP field is constructed as a model that is maximally smooth and, at the same time, has a power-spectral decay common to all fields produced by the same source. The applied regularization alleviates the singularity associated with the wavenumber-domain RTP operator, and the imposed power spectral decay ensures that the constructed RTP field has the correct spectral content. As a result, the algorithm can perform the reduction to the pole stably at any magnetic latitude, and the constructed RTP field yields a good representation of the true field at the pole even when the reduction is carried out at the equator.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Center of Mass Estimation of Simple Shaped Magnetic Bodies Using Eigenvectors of Computed Magnetic Gradient Tensor

Computed Magnetic Gradient Tensor (CMGT) includes the first derivatives of three components of magnetic field of a body. At the eigenvector analysis of Gravity Gradient Tensors (GGT) for a line of poles and point pole, the eigenvectors of the largest eigenvalues (first eigenvectors) point precisely toward the Center of Mass (COM) of a body. However, due to the nature of the magnetic field, it i...

متن کامل

Investigation of unbalanced magnetic force in permanent magnet brushless dc machines with diametrically asymmetric winding

The purpose of this paper is the calculation of Unbalanced Magnetic Force (UMF) in permanent magnet brushless DC (PMBLDC) machines with diametrically asymmetric winding and investigation of UMF variations in the presence of phase advance angle. This paper presents an analytical model of UMF in surface mounted PMBLDC machines that have a fractional ratio of slot number to pole number. This model...

متن کامل

A Reduction Method of Cogging Torque for Magnetic Gears

Nowadays, magnetic gears (MGs) have become an alternative choice for mechanical gears because of their low maintenance, improved durability, indirect contact between inner and outer rotors, no lubrication, and high efficiency. Generally, although these advantages, MGs suffer from inherent issues, mainly the cogging torque. Therefore, cogging torque mitigation has become an active research area....

متن کامل

North–south topographic slope asymmetry on Mars: Evidence for insolation-related erosion at high obliquity

[1] A map of north–south subkilometer-scale slope asymmetry on Mars obtained from statistical analysis of along-track MOLA topographic profiles reveals welldefined zonal belts of north–south slope asymmetry at 40–50 latitude in both hemispheres. In these narrow anomalous belts the pole-facing slopes are systematically gentler than equator-facing slopes. This asymmetry is especially pronounced f...

متن کامل

Thrust Ripple Reduction of Permanent Magnet Linear Synchronous Motor Based on Improved Pole Shape for Electromagnetic Launcher System

In this paper, a new design of permanent magnet linear synchronous motor (PMLSM) for electromagnetic launcher system (EMLs) has been investigated in terms of the requisite amount of average launching thrust force and thrust force ripple minimization through finite element method. EMLs are a kind of technology used to develop thrust force and launch heavy loads with different applications includ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2001