Characteristics of the Ionospheric Mid-Latitude Trough Measured by Topside Sounders in 1960–70s
The ionospheric mid-latitude trough (IMT) is the electron density depletion phenomenon in the F region during nighttime. It has been suggested that the IMT is the result of complex plasma processes coupled to the magnetosphere. In order to statistically investigate the characteristics of the IMT, we...
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| Format: | Article |
| Language: | English |
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The Korean Space Science Society
2019-09-01
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| Series: | Journal of Astronomy and Space Sciences |
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| Online Access: | https://doi.org/10.5140/JASS.2019.36.3.121 |
| _version_ | 1797369796582440960 |
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| author | Junseok Hong Yongha Kim Young-Sook Lee |
| author_facet | Junseok Hong Yongha Kim Young-Sook Lee |
| author_sort | Junseok Hong |
| collection | DOAJ |
| description | The ionospheric mid-latitude trough (IMT) is the electron density depletion phenomenon in the F region during nighttime. It has been suggested that the IMT is the result of complex plasma processes coupled to the magnetosphere. In order to statistically investigate the characteristics of the IMT, we analyze topside sounding data from Alouette and ISIS satellites in 1960s and 1970s. The IMT position is almost constant for seasons and solar activities whereas the IMT depth ratio and the IMT feature are stronger and clearer in the winter hemisphere under solar minimum condition. We also calculated transition heights at which the densities of oxygen ions and hydrogen/helium ions are equal. Transition heights are generally higher in daytime and lower in nighttime, but the opposite aspects are seen in the IMT region. Utilizing the Incoherent Scatter Radar (ISR) electron temperature measurements, we find that the electron temperature in the IMT region is enhanced at night during winter. The increase of electron temperature may cause fast transport of the ionospheric plasma to the magnetosphere via ambipolar diffusion, resulting in the IMT depletion. This mechanism of the IMT may work in addition to the simply prolonged recombination of ions proposed by the traditional stagnation model. |
| first_indexed | 2024-03-08T17:52:05Z |
| format | Article |
| id | doaj.art-5623337808ef458495b95849efe1b740 |
| institution | Directory Open Access Journal |
| issn | 2093-5587 2093-1409 |
| language | English |
| last_indexed | 2024-03-08T17:52:05Z |
| publishDate | 2019-09-01 |
| publisher | The Korean Space Science Society |
| record_format | Article |
| series | Journal of Astronomy and Space Sciences |
| spelling | doaj.art-5623337808ef458495b95849efe1b7402024-01-02T07:03:10ZengThe Korean Space Science SocietyJournal of Astronomy and Space Sciences2093-55872093-14092019-09-0136312113110.5140/JASS.2019.36.2.121Characteristics of the Ionospheric Mid-Latitude Trough Measured by Topside Sounders in 1960–70sJunseok Hong0Yongha Kim1Young-Sook Lee2Department of Astronomy, Space Science and Geology, Chungnam National University, Daejeon 34134, KoreaDepartment of Astronomy, Space Science and Geology, Chungnam National University, Daejeon 34134, KoreaDepartment of Astronomy, Space Science and Geology, Chungnam National University, Daejeon 34134, KoreaThe ionospheric mid-latitude trough (IMT) is the electron density depletion phenomenon in the F region during nighttime. It has been suggested that the IMT is the result of complex plasma processes coupled to the magnetosphere. In order to statistically investigate the characteristics of the IMT, we analyze topside sounding data from Alouette and ISIS satellites in 1960s and 1970s. The IMT position is almost constant for seasons and solar activities whereas the IMT depth ratio and the IMT feature are stronger and clearer in the winter hemisphere under solar minimum condition. We also calculated transition heights at which the densities of oxygen ions and hydrogen/helium ions are equal. Transition heights are generally higher in daytime and lower in nighttime, but the opposite aspects are seen in the IMT region. Utilizing the Incoherent Scatter Radar (ISR) electron temperature measurements, we find that the electron temperature in the IMT region is enhanced at night during winter. The increase of electron temperature may cause fast transport of the ionospheric plasma to the magnetosphere via ambipolar diffusion, resulting in the IMT depletion. This mechanism of the IMT may work in addition to the simply prolonged recombination of ions proposed by the traditional stagnation model.https://doi.org/10.5140/JASS.2019.36.3.121onospheric mid-latitude trough (IMT)topside sounder |
| spellingShingle | Junseok Hong Yongha Kim Young-Sook Lee Characteristics of the Ionospheric Mid-Latitude Trough Measured by Topside Sounders in 1960–70s Journal of Astronomy and Space Sciences onospheric mid-latitude trough (IMT) topside sounder |
| title | Characteristics of the Ionospheric Mid-Latitude Trough Measured by Topside Sounders in 1960–70s |
| title_full | Characteristics of the Ionospheric Mid-Latitude Trough Measured by Topside Sounders in 1960–70s |
| title_fullStr | Characteristics of the Ionospheric Mid-Latitude Trough Measured by Topside Sounders in 1960–70s |
| title_full_unstemmed | Characteristics of the Ionospheric Mid-Latitude Trough Measured by Topside Sounders in 1960–70s |
| title_short | Characteristics of the Ionospheric Mid-Latitude Trough Measured by Topside Sounders in 1960–70s |
| title_sort | characteristics of the ionospheric mid latitude trough measured by topside sounders in 1960 70s |
| topic | onospheric mid-latitude trough (IMT) topside sounder |
| url | https://doi.org/10.5140/JASS.2019.36.3.121 |
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