Generation and evolution of interplanetary slow shocks
It is well known that most MHD shocks observed within 1 AU are MHD fast shocks. Only a very limited number of MHD slow shocks are observed within 1 AU. In order to understand why there are only a few MHD slow shocks observed within 1 AU, we use a one-dimensional, time-dependent MHD code with an adap...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
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| Series: | Annales Geophysicae |
| Online Access: | http://www.ann-geophys.net/14/375/1996/angeo-14-375-1996.html |
| _version_ | 1828288695615094784 |
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| author | C.-C. Wu S. T. Wu M. Dryer |
| author_facet | C.-C. Wu S. T. Wu M. Dryer |
| author_sort | C.-C. Wu |
| collection | DOAJ |
| description | It is well known that most MHD shocks observed within 1 AU are MHD fast shocks. Only a very limited number of MHD slow shocks are observed within 1 AU. In order to understand why there are only a few MHD slow shocks observed within 1 AU, we use a one-dimensional, time-dependent MHD code with an adaptive grid to study the generation and evolution of interplanetary slow shocks (ISS) in the solar wind. Results show that a negative, nearly square-wave perturbation will generate a pair of slow shocks (a forward and a reverse slow shock). In addition, the forward and the reverse slow shocks can pass through each other without destroying their characteristics, but the propagating speeds for both shocks are decreased. A positive, square-wave perturbation will generate both slow and fast shocks. When a forward slow shock (FSS) propagates behind a forward fast shock (FFS), the former experiences a decreasing Mach number. In addition, the FSS always disappears within a distance of 150<i>R</i><sub>&amp;odot;</sub> (where <i>R</i><sub>&amp;odot;</sub> is one solar radius) from the Sun when there is a forward fast shock (with Mach number &#x2265;1.7) propagating in front of the FSS. In all tests that we have performed, we have not discovered that the FSS (or reverse slow shock) evolves into a FFS (or reverse fast shock). Thus, we do not confirm the FSS-FFS evolution as suggested by Whang (1987). |
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| id | doaj.art-5614b5d30117400295656073d7de5a4d |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-04-13T10:09:44Z |
| publisher | Copernicus Publications |
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| series | Annales Geophysicae |
| spelling | doaj.art-5614b5d30117400295656073d7de5a4d2022-12-22T02:50:58ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-0576144375382Generation and evolution of interplanetary slow shocksC.-C. WuS. T. WuM. DryerIt is well known that most MHD shocks observed within 1 AU are MHD fast shocks. Only a very limited number of MHD slow shocks are observed within 1 AU. In order to understand why there are only a few MHD slow shocks observed within 1 AU, we use a one-dimensional, time-dependent MHD code with an adaptive grid to study the generation and evolution of interplanetary slow shocks (ISS) in the solar wind. Results show that a negative, nearly square-wave perturbation will generate a pair of slow shocks (a forward and a reverse slow shock). In addition, the forward and the reverse slow shocks can pass through each other without destroying their characteristics, but the propagating speeds for both shocks are decreased. A positive, square-wave perturbation will generate both slow and fast shocks. When a forward slow shock (FSS) propagates behind a forward fast shock (FFS), the former experiences a decreasing Mach number. In addition, the FSS always disappears within a distance of 150<i>R</i><sub>&amp;odot;</sub> (where <i>R</i><sub>&amp;odot;</sub> is one solar radius) from the Sun when there is a forward fast shock (with Mach number &#x2265;1.7) propagating in front of the FSS. In all tests that we have performed, we have not discovered that the FSS (or reverse slow shock) evolves into a FFS (or reverse fast shock). Thus, we do not confirm the FSS-FFS evolution as suggested by Whang (1987).http://www.ann-geophys.net/14/375/1996/angeo-14-375-1996.html |
| spellingShingle | C.-C. Wu S. T. Wu M. Dryer Generation and evolution of interplanetary slow shocks Annales Geophysicae |
| title | Generation and evolution of interplanetary slow shocks |
| title_full | Generation and evolution of interplanetary slow shocks |
| title_fullStr | Generation and evolution of interplanetary slow shocks |
| title_full_unstemmed | Generation and evolution of interplanetary slow shocks |
| title_short | Generation and evolution of interplanetary slow shocks |
| title_sort | generation and evolution of interplanetary slow shocks |
| url | http://www.ann-geophys.net/14/375/1996/angeo-14-375-1996.html |
| work_keys_str_mv | AT ccwu generationandevolutionofinterplanetaryslowshocks AT stwu generationandevolutionofinterplanetaryslowshocks AT mdryer generationandevolutionofinterplanetaryslowshocks |