Failures of Minimum Variance Analysis in Diagnosing Planar Structures in Space
Minimum variance analysis of the magnetic field (MVAB), among various techniques of planar structure analysis, is most widely used for its numerical simplicity and loose requirements for data. Through a large number of studies based on MVAB, a global picture of the solar wind intermittency has been...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2023-01-01
|
| Series: | The Astrophysical Journal Supplement Series |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4365/acdd58 |
| _version_ | 1827825658942717952 |
|---|---|
| author | Y. Y. Liu J. B. Cao H. S. Fu Z. Wang Z. Z. Guo R. J. He |
| author_facet | Y. Y. Liu J. B. Cao H. S. Fu Z. Wang Z. Z. Guo R. J. He |
| author_sort | Y. Y. Liu |
| collection | DOAJ |
| description | Minimum variance analysis of the magnetic field (MVAB), among various techniques of planar structure analysis, is most widely used for its numerical simplicity and loose requirements for data. Through a large number of studies based on MVAB, a global picture of the solar wind intermittency has been established. However, the huge discrepancy between the results from MVAB and other techniques like timing/triangulation implies that the uncertainty of MVAB is a crucial issue that is not fully understood. Utilizing Cluster data, we establish a data set comprised of 6752 discontinuities, whose orientations are precisely determined by timing, as a benchmark for testing MVAB. We find that the scatter of the MVAB normals around the timing normal can be reduced by elevating the threshold for the eigenvalue ratio λ _2 / λ _3 and narrowing the data window to which MVAB is applied. The misidentification of discontinuities with $\left|{B}_{N}\right|/| {\boldsymbol{B}}| $ < 0.4, Δ∣ B ∣/∣ B ∣ < 0.2 as rotational discontinuities (RDs, identified by $\left|{B}_{N}\right|/| {\boldsymbol{B}}| $ > 0.4, Δ∣ B ∣/∣ B ∣ < 0.2) is proved to be a major and inherent defect of MVAB, which can occur even when λ _2 / λ _3 is large. Such a misidentification process is revealed to be related to a special discontinuity geometry. It also explains the false RD predominance reported by previous studies based on MVAB. Finally, we provide advice for the application of MVAB and discuss the possibility of obtaining the real statistical properties of interplanetary discontinuities by using MVAB. |
| first_indexed | 2024-03-12T02:53:51Z |
| format | Article |
| id | doaj.art-19666bd3213c4baaad3b8ca33e06dbcf |
| institution | Directory Open Access Journal |
| issn | 0067-0049 |
| language | English |
| last_indexed | 2024-03-12T02:53:51Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Supplement Series |
| spelling | doaj.art-19666bd3213c4baaad3b8ca33e06dbcf2023-09-03T15:25:46ZengIOP PublishingThe Astrophysical Journal Supplement Series0067-00492023-01-0126711310.3847/1538-4365/acdd58Failures of Minimum Variance Analysis in Diagnosing Planar Structures in SpaceY. Y. Liu0https://orcid.org/0000-0002-0765-1709J. B. Cao1https://orcid.org/0000-0002-5637-2976H. S. Fu2https://orcid.org/0000-0002-4701-7219Z. Wang3https://orcid.org/0000-0002-1720-964XZ. Z. Guo4https://orcid.org/0000-0002-4479-7045R. J. He5School of Space and Environment, Beihang University , Beijing, 100191, People’s Republic of China ; jbcao@buaa.edu.cn, huishanf@gmail.com; Key Laboratory of Space Environment Monitoring and Information Processing, Ministry of Industry and Information Technology , Beijing, 100191, People’s Republic of ChinaSchool of Space and Environment, Beihang University , Beijing, 100191, People’s Republic of China ; jbcao@buaa.edu.cn, huishanf@gmail.com; Key Laboratory of Space Environment Monitoring and Information Processing, Ministry of Industry and Information Technology , Beijing, 100191, People’s Republic of ChinaSchool of Space and Environment, Beihang University , Beijing, 100191, People’s Republic of China ; jbcao@buaa.edu.cn, huishanf@gmail.com; Key Laboratory of Space Environment Monitoring and Information Processing, Ministry of Industry and Information Technology , Beijing, 100191, People’s Republic of ChinaSchool of Space and Environment, Beihang University , Beijing, 100191, People’s Republic of China ; jbcao@buaa.edu.cn, huishanf@gmail.com; Key Laboratory of Space Environment Monitoring and Information Processing, Ministry of Industry and Information Technology , Beijing, 100191, People’s Republic of ChinaSchool of Space and Environment, Beihang University , Beijing, 100191, People’s Republic of China ; jbcao@buaa.edu.cn, huishanf@gmail.com; Key Laboratory of Space Environment Monitoring and Information Processing, Ministry of Industry and Information Technology , Beijing, 100191, People’s Republic of ChinaSchool of Space and Environment, Beihang University , Beijing, 100191, People’s Republic of China ; jbcao@buaa.edu.cn, huishanf@gmail.com; Key Laboratory of Space Environment Monitoring and Information Processing, Ministry of Industry and Information Technology , Beijing, 100191, People’s Republic of ChinaMinimum variance analysis of the magnetic field (MVAB), among various techniques of planar structure analysis, is most widely used for its numerical simplicity and loose requirements for data. Through a large number of studies based on MVAB, a global picture of the solar wind intermittency has been established. However, the huge discrepancy between the results from MVAB and other techniques like timing/triangulation implies that the uncertainty of MVAB is a crucial issue that is not fully understood. Utilizing Cluster data, we establish a data set comprised of 6752 discontinuities, whose orientations are precisely determined by timing, as a benchmark for testing MVAB. We find that the scatter of the MVAB normals around the timing normal can be reduced by elevating the threshold for the eigenvalue ratio λ _2 / λ _3 and narrowing the data window to which MVAB is applied. The misidentification of discontinuities with $\left|{B}_{N}\right|/| {\boldsymbol{B}}| $ < 0.4, Δ∣ B ∣/∣ B ∣ < 0.2 as rotational discontinuities (RDs, identified by $\left|{B}_{N}\right|/| {\boldsymbol{B}}| $ > 0.4, Δ∣ B ∣/∣ B ∣ < 0.2) is proved to be a major and inherent defect of MVAB, which can occur even when λ _2 / λ _3 is large. Such a misidentification process is revealed to be related to a special discontinuity geometry. It also explains the false RD predominance reported by previous studies based on MVAB. Finally, we provide advice for the application of MVAB and discuss the possibility of obtaining the real statistical properties of interplanetary discontinuities by using MVAB.https://doi.org/10.3847/1538-4365/acdd58Interplanetary discontinuitiesAstronomy data analysisInterplanetary magnetic fieldsSolar wind |
| spellingShingle | Y. Y. Liu J. B. Cao H. S. Fu Z. Wang Z. Z. Guo R. J. He Failures of Minimum Variance Analysis in Diagnosing Planar Structures in Space The Astrophysical Journal Supplement Series Interplanetary discontinuities Astronomy data analysis Interplanetary magnetic fields Solar wind |
| title | Failures of Minimum Variance Analysis in Diagnosing Planar Structures in Space |
| title_full | Failures of Minimum Variance Analysis in Diagnosing Planar Structures in Space |
| title_fullStr | Failures of Minimum Variance Analysis in Diagnosing Planar Structures in Space |
| title_full_unstemmed | Failures of Minimum Variance Analysis in Diagnosing Planar Structures in Space |
| title_short | Failures of Minimum Variance Analysis in Diagnosing Planar Structures in Space |
| title_sort | failures of minimum variance analysis in diagnosing planar structures in space |
| topic | Interplanetary discontinuities Astronomy data analysis Interplanetary magnetic fields Solar wind |
| url | https://doi.org/10.3847/1538-4365/acdd58 |
| work_keys_str_mv | AT yyliu failuresofminimumvarianceanalysisindiagnosingplanarstructuresinspace AT jbcao failuresofminimumvarianceanalysisindiagnosingplanarstructuresinspace AT hsfu failuresofminimumvarianceanalysisindiagnosingplanarstructuresinspace AT zwang failuresofminimumvarianceanalysisindiagnosingplanarstructuresinspace AT zzguo failuresofminimumvarianceanalysisindiagnosingplanarstructuresinspace AT rjhe failuresofminimumvarianceanalysisindiagnosingplanarstructuresinspace |