• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to previous page

Maximum Likelihood Parameter Estimation and Simulation of Damped-Type ULF Waves Using a Workstation

Research Project

Project/Area Number 05640488
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field Space and upper atmospheric physics
Research InstitutionKYUSHU UNIVERSITY

Principal Investigator

ITONAGA Masahiro  Kyushu University, Computation Center, Assistant Professor, 工学部, 講師 (60213104)

Project Period (FY) 1993 – 1994
Project Status Completed (Fiscal Year 1994)
Budget Amount *help
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1994: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1993: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywordsworkstation / damped-type ULF wave / parameter estimation / maximum likelihood method / modified Pisarenko method / piecewise cubic polynomial / PCP filter / simulation / ULF波動 / 最尤パラメータ推定 / データ平滑化 / 離散的周波数構造 / 磁力線共鳴 / 電離層電気伝導度
Research Abstract

Various computer programs for data processing have been developed on a workstation, and parameter estimations and simulations of damped-type ULF waves have been per-formed using the workstation. Research results are as follows : 1.While a method for fitting a piecewise cubic polynomial (PCP) to a sequence of data, which corresponds to a nonlinear lowpass filter and is named a PCP filter, is accompanied with a parameter mu determing the degree of smoothing, the relation between mu and its cutoff frequency has been found.The PCP filter is effective in separating Psc's from main impulses of SSC's. 2. Although a modified Pisarenko method (MPM) is inferior in estimation ability to the maximum likelihood method (MLM), it is one of the methods with the highest perfor-mance except for the MLM and is much superior in computational cost to the MLM.It has been used in the analysis of the Psc's. 3. The shape of the waveform of low-latitude and equatorial Psc's is consistently ordered by local time ; it is steeper near noon and has a more moderate slope near midnight. They have globally almost identical dominant frequencies which agree well with those of Pi2's. These indicate that the Psc's are not cavity-mode oscillations but compressional hydromagnetic (HM) waves propagating from dayside to nightside. 4. The self-consistent ionospheric boundary conditions, which de-scribe the interaction between HM waves and the anisotropically conducting ionosphere, have been derived in the form convenient for the eigenmode analysis of coupled HM waves in the magnetosphere-ionosphere system.

Report

(3 results)
  • 1994 Annual Research Report   Final Research Report Summary
  • 1993 Annual Research Report
  • Research Products

    (9 results)

All Other

All Publications (9 results)

  • [Publications] A.Yoshikawa: "Effect of the ionospheric induction current on magnetohydrodynamic waves in the magnetosphere" Proceedings of the NIPR Symposium on Upper Atmosphere Physics(in press). 8. (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] 糸長雅弘: "区分的3次多項式による非線形フィルタリング" 日本応用数理学会論文誌. (投稿中).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] M.Itonaga: "Global Structure of Low-Latitude and Equatorial Geomagnetic Pulsations Associated with Storm Sudden Commencements" Journal of Geomagnetism and Geoelectricity. (submitted).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] M.Itonaga: "Interaction between Hydromagnetic Waves and the Anisotropically Conducting Ionosphere" Journal of Geomagnetism and Geoelectricity. (submitted).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] A.Yoshikawa et al.: "Effect of the ionospheric induction current on magneto-hydrodynamic waves in the magnetosphere" Proceedings of the NIPR Symposium on Upper Atmos-phere Physics. No.8 (in Press). (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] M.Itonaga: "Nonlinear filtering using a piecewise cubic polynomial" submitted to Transactions of the Japan Society for Indus-trial and Applied Mathemat-ics.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] M.Itonaga et al.: "Global structure of low-latitude and equatorial geo-magnetic pulsations associated with storm sudden com-mencements" submitted to Journal of Ge-omagnetism and Geoelectric-ity.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] M.Itonaga et al.: "Interaction between hydromagnetic waves and the anisotropically conducting ionosphere" submitted to Journal of Ge-omagnetism and Geoelectric-ity.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] A,Yoshikawa,M.Itonaga,T.I.Kitamura: "Effect of the ionospheric induction current on magnetohydrodynamic waves in the magnetosphere" Proceedings of the NIPR Symposium on Upper Atmosphere Physics. 8(in press). (1995)

    • Related Report
      1994 Annual Research Report

URL: 

Published: 1993-04-01   Modified: 2016-04-21  

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi