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Roland T. Tsunoda - One of the best experts on this subject based on the ideXlab platform.
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Post-sunset rise oF equatorial F Layer—or upwelling growth?
Progress in Earth and Planetary Science, 2018Co-Authors: Roland T. Tsunoda, Susumu Saito, Trang T. NguyenAbstract:According to the so-called upwelling paradigm, development oF equatorial plasma bubbles (EPBs) involves (1) appearance oF an upwelling (i.e., local upliFt with a zonal width oF ~ 400 km) in the bottomside oF the equatorial F Layer, (2) its growth via the F-region interchange instability during the post-sunset rise (PSSR) oF the F Layer, and (3) launching oF EPBs, which starts near the end oF PSSR, From within the conFines oF the upwelling. In this description, the PSSR is presumed to be the primary driver oF the paradigm, with upwelling growth dependent on PSSR strength. As constructed, the paradigm describes EPB development when PSSR is strong (i.e., high solar activity), but not when it is weak. We, show, For the First time, that when PSSR is weak (e.g., low solar activity), upwelling growth can still be comparable in strength to what would be considered a strong PSSR, and that this growth drives EPB development. Given that EPBs do not develop outside oF upwellings, regardless oF solar activity, we are led to conclude, against mainstream thinking, that the controlling driver For EPB development is upwelling growth, not PSSR. For continued progress toward understanding EPB development, a crucial next step is to identiFy the source mechanism For upwelling growth, especially when PSSR is weak, and to better understand the complexities oF the underlying physics.
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post sunset rise oF equatorial F Layer or upwelling growth
Progress in Earth and Planetary Science, 2018Co-Authors: Roland T. Tsunoda, Susumu Saito, Trang T. NguyenAbstract:According to the so-called upwelling paradigm, development oF equatorial plasma bubbles (EPBs) involves (1) appearance oF an upwelling (i.e., local upliFt with a zonal width oF ~ 400 km) in the bottomside oF the equatorial F Layer, (2) its growth via the F-region interchange instability during the post-sunset rise (PSSR) oF the F Layer, and (3) launching oF EPBs, which starts near the end oF PSSR, From within the conFines oF the upwelling. In this description, the PSSR is presumed to be the primary driver oF the paradigm, with upwelling growth dependent on PSSR strength. As constructed, the paradigm describes EPB development when PSSR is strong (i.e., high solar activity), but not when it is weak. We, show, For the First time, that when PSSR is weak (e.g., low solar activity), upwelling growth can still be comparable in strength to what would be considered a strong PSSR, and that this growth drives EPB development. Given that EPBs do not develop outside oF upwellings, regardless oF solar activity, we are led to conclude, against mainstream thinking, that the controlling driver For EPB development is upwelling growth, not PSSR. For continued progress toward understanding EPB development, a crucial next step is to identiFy the source mechanism For upwelling growth, especially when PSSR is weak, and to better understand the complexities oF the underlying physics.
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On the post‐sunset rise oF the equatorial F Layer and superposed upwellings and bubbles
Geophysical Research Letters, 2007Co-Authors: Roland T. Tsunoda, Warner L. EcklundAbstract:[1] Usual practice has been to describe the post-sunset rise (PSSR) oF the equatorial F Layer with the vertical driFt velocity measured overhead, as a Function oF local time, by a ground-based sensor. However, with the Finding that large-scale wave structure (LSWS) develops with its own eastward polarization electric Field, during a PSSR, the measured upward velocity must now be thought oF as containing two components, one associated with PSSR, and the other with LSWS. This distinction may hold the key to understanding the lack oF correlation, on a day-to-day basis, between measured vertical driFt and ensuing plasma structure in the Form oF plasma bubbles. Measurements oF backscatter From the bottomside oF the F Layer, using a three-beam radar at Pohnpei, are presented in this paper to Further validate this interpretation.
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on the post sunset rise oF the equatorial F Layer and superposed upwellings and bubbles
Geophysical Research Letters, 2007Co-Authors: Roland T. Tsunoda, Warner L. EcklundAbstract:[1] Usual practice has been to describe the post-sunset rise (PSSR) oF the equatorial F Layer with the vertical driFt velocity measured overhead, as a Function oF local time, by a ground-based sensor. However, with the Finding that large-scale wave structure (LSWS) develops with its own eastward polarization electric Field, during a PSSR, the measured upward velocity must now be thought oF as containing two components, one associated with PSSR, and the other with LSWS. This distinction may hold the key to understanding the lack oF correlation, on a day-to-day basis, between measured vertical driFt and ensuing plasma structure in the Form oF plasma bubbles. Measurements oF backscatter From the bottomside oF the F Layer, using a three-beam radar at Pohnpei, are presented in this paper to Further validate this interpretation.
Warner L. Ecklund - One of the best experts on this subject based on the ideXlab platform.
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On the post‐sunset rise oF the equatorial F Layer and superposed upwellings and bubbles
Geophysical Research Letters, 2007Co-Authors: Roland T. Tsunoda, Warner L. EcklundAbstract:[1] Usual practice has been to describe the post-sunset rise (PSSR) oF the equatorial F Layer with the vertical driFt velocity measured overhead, as a Function oF local time, by a ground-based sensor. However, with the Finding that large-scale wave structure (LSWS) develops with its own eastward polarization electric Field, during a PSSR, the measured upward velocity must now be thought oF as containing two components, one associated with PSSR, and the other with LSWS. This distinction may hold the key to understanding the lack oF correlation, on a day-to-day basis, between measured vertical driFt and ensuing plasma structure in the Form oF plasma bubbles. Measurements oF backscatter From the bottomside oF the F Layer, using a three-beam radar at Pohnpei, are presented in this paper to Further validate this interpretation.
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on the post sunset rise oF the equatorial F Layer and superposed upwellings and bubbles
Geophysical Research Letters, 2007Co-Authors: Roland T. Tsunoda, Warner L. EcklundAbstract:[1] Usual practice has been to describe the post-sunset rise (PSSR) oF the equatorial F Layer with the vertical driFt velocity measured overhead, as a Function oF local time, by a ground-based sensor. However, with the Finding that large-scale wave structure (LSWS) develops with its own eastward polarization electric Field, during a PSSR, the measured upward velocity must now be thought oF as containing two components, one associated with PSSR, and the other with LSWS. This distinction may hold the key to understanding the lack oF correlation, on a day-to-day basis, between measured vertical driFt and ensuing plasma structure in the Form oF plasma bubbles. Measurements oF backscatter From the bottomside oF the F Layer, using a three-beam radar at Pohnpei, are presented in this paper to Further validate this interpretation.
Kangkang Liu - One of the best experts on this subject based on the ideXlab platform.
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The linear growth rate oF Rayleigh–Taylor instability in ionospheric F Layer
2019Co-Authors: Kangkang LiuAbstract:Abstract. It is generally considered that the perturbation electric Field generated by the charge accumulation caused by the current divergence is the driving Force For Rayleigh–Taylor instability (RTI) in plasma. However, in previous calculation oF the linear growth rate oF RTI the current continuity equation was applied, which means the contribution oF charge accumulation to the growth oF RTI was ignored. Applying the perturbation electric Field and the current continuity equation simultaneously in calculating the linear growth rate oF RTI oF the ionospheric F Layer will give erroneous results. In this paper, we calculated the linear growth rate oF RTI with the standard instability analysis method. The charge conservation equation was used in the calculation instead oF the current continuity to study the contribution oF charge accumulation to the growth oF RTI. The results show that the contribution oF charge accumulation to the linear growth rate oF RTI is proportional to the ratio oF AlFven speed to the light speed. In ionospheric F Layer the ratio is small, the contribution oF charge accumulation to the growth oF RTI is negligible. This indicates that the previous physical description oF the RTI in the ionospheric F Layer is wrong and a new physical description oF RTI is needed. In the new physical description perturbation electric Field and charge accumulation is not the cause, but the result oF RTI. In ionospheric Layer, background electric Field and neutral wind velocity have no eFFect on the linear growth rate oF RTI.
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the linear growth rate oF rayleigh taylor instability in ionospheric F Layer
Annales Geophysicae, 2019Co-Authors: Kangkang LiuAbstract:Abstract. It is generally considered that the perturbation electric Field generated by the charge accumulation caused by the current divergence is the driving Force For Rayleigh–Taylor instability (RTI) in plasma. However, in previous calculation oF the linear growth rate oF RTI the current continuity equation was applied, which means the contribution oF charge accumulation to the growth oF RTI was ignored. Applying the perturbation electric Field and the current continuity equation simultaneously in calculating the linear growth rate oF RTI oF the ionospheric F Layer will give erroneous results. In this paper, we calculated the linear growth rate oF RTI with the standard instability analysis method. The charge conservation equation was used in the calculation instead oF the current continuity to study the contribution oF charge accumulation to the growth oF RTI. The results show that the contribution oF charge accumulation to the linear growth rate oF RTI is proportional to the ratio oF AlFven speed to the light speed. In ionospheric F Layer the ratio is small, the contribution oF charge accumulation to the growth oF RTI is negligible. This indicates that the previous physical description oF the RTI in the ionospheric F Layer is wrong and a new physical description oF RTI is needed. In the new physical description perturbation electric Field and charge accumulation is not the cause, but the result oF RTI. In ionospheric Layer, background electric Field and neutral wind velocity have no eFFect on the linear growth rate oF RTI.
Trang T. Nguyen - One of the best experts on this subject based on the ideXlab platform.
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Post-sunset rise oF equatorial F Layer—or upwelling growth?
Progress in Earth and Planetary Science, 2018Co-Authors: Roland T. Tsunoda, Susumu Saito, Trang T. NguyenAbstract:According to the so-called upwelling paradigm, development oF equatorial plasma bubbles (EPBs) involves (1) appearance oF an upwelling (i.e., local upliFt with a zonal width oF ~ 400 km) in the bottomside oF the equatorial F Layer, (2) its growth via the F-region interchange instability during the post-sunset rise (PSSR) oF the F Layer, and (3) launching oF EPBs, which starts near the end oF PSSR, From within the conFines oF the upwelling. In this description, the PSSR is presumed to be the primary driver oF the paradigm, with upwelling growth dependent on PSSR strength. As constructed, the paradigm describes EPB development when PSSR is strong (i.e., high solar activity), but not when it is weak. We, show, For the First time, that when PSSR is weak (e.g., low solar activity), upwelling growth can still be comparable in strength to what would be considered a strong PSSR, and that this growth drives EPB development. Given that EPBs do not develop outside oF upwellings, regardless oF solar activity, we are led to conclude, against mainstream thinking, that the controlling driver For EPB development is upwelling growth, not PSSR. For continued progress toward understanding EPB development, a crucial next step is to identiFy the source mechanism For upwelling growth, especially when PSSR is weak, and to better understand the complexities oF the underlying physics.
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post sunset rise oF equatorial F Layer or upwelling growth
Progress in Earth and Planetary Science, 2018Co-Authors: Roland T. Tsunoda, Susumu Saito, Trang T. NguyenAbstract:According to the so-called upwelling paradigm, development oF equatorial plasma bubbles (EPBs) involves (1) appearance oF an upwelling (i.e., local upliFt with a zonal width oF ~ 400 km) in the bottomside oF the equatorial F Layer, (2) its growth via the F-region interchange instability during the post-sunset rise (PSSR) oF the F Layer, and (3) launching oF EPBs, which starts near the end oF PSSR, From within the conFines oF the upwelling. In this description, the PSSR is presumed to be the primary driver oF the paradigm, with upwelling growth dependent on PSSR strength. As constructed, the paradigm describes EPB development when PSSR is strong (i.e., high solar activity), but not when it is weak. We, show, For the First time, that when PSSR is weak (e.g., low solar activity), upwelling growth can still be comparable in strength to what would be considered a strong PSSR, and that this growth drives EPB development. Given that EPBs do not develop outside oF upwellings, regardless oF solar activity, we are led to conclude, against mainstream thinking, that the controlling driver For EPB development is upwelling growth, not PSSR. For continued progress toward understanding EPB development, a crucial next step is to identiFy the source mechanism For upwelling growth, especially when PSSR is weak, and to better understand the complexities oF the underlying physics.
S G Sumod - One of the best experts on this subject based on the ideXlab platform.
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investigation on F Layer height rise and equatorial spread F onset time signature oF standing large scale wave
Social Work, 2015Co-Authors: L M Joshi, S Balwada, T K Pant, S G SumodAbstract:Equatorial spread F observations have been categorized into three categories based on ionograms recorded over Sriharikota. First category comprised cases where the onset oF equatorial spread F (ESF) was concurrent with the peak h′F time. Second and third categories comprised cases where the onset oF ESF happened with a delay oF 30 min and more than 30 min, respectively, with reFerence to the peak h′F time. Average peak h′F in the First category was more than 35 km higher than that in the second and third categories. Also, the peak vertical (upward) plasma driFt was higher in the First category. Assuming the genesis oF F region irregularity to have happened at or beFore the time oF F Layer attaining the peak height, late onset oF ESF indicates the genesis oF irregularities to have happened westward oF Sriharikota. The Fact that the peak h′F values were remarkably diFFerent in the three categories indicates a zonal variation oF eastward electric Field and postsunset height rise oF F Layer. The relative magnitude oF the F Layer height rise in the three diFFerent categories over Sriharikota has also been Found to be signiFicantly diFFerent than that over Thumba, an equatorial (magnetic) station located ~360 km westward oF Sriharikota longitude. This scenario points toward the existence oF a large-scale zonal standing wave in the F Layer and its important role in F region instability process. Results presented in the manuscript have been discussed in the light oF current understanding on the large-scale wave structure.