Impact of solar wind depression on the dayside magnetosphere under northward interplanetary magnetic field
We present a follow up study of the sensitivity of the Earth's magnetosphere to solar wind activity using a particles-in-cell model (Baraka and Ben Jaffel, 2007), but here during northward Interplanetary Magnetic Field (IMF). The formation of the magnetospheric cavity and its elongation arou...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2011-01-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/29/31/2011/angeo-29-31-2011.pdf |
| _version_ | 1818547581659119616 |
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| author | S. Baraka S. Baraka L. Ben-Jaffel L. Ben-Jaffel |
| author_facet | S. Baraka S. Baraka L. Ben-Jaffel L. Ben-Jaffel |
| author_sort | S. Baraka |
| collection | DOAJ |
| description | We present a follow up study of the sensitivity of the Earth's magnetosphere to solar
wind activity using a particles-in-cell model (Baraka and Ben Jaffel, 2007), but
here during northward Interplanetary Magnetic Field (IMF). The formation of the
magnetospheric cavity and its elongation around the planet is obtained with the
classical structure of a magnetosphere with parallel lobes. An impulsive
disturbance is then applied to the system by changing the bulk velocity of the
solar wind to simulate a decrease in the solar wind dynamic pressure followed
by its recovery. In response to the imposed drop in the solar wind velocity,
a gap (abrupt depression) in the incoming solar wind plasma appears moving
toward the Earth. The gap's size is a ~15 <I>R</I><sub>E</sub> and is comparable
to the sizes previously obtained for both <I>B</I><sub>z</sub><0 and <I>B</I><sub>z</sub>=0.
During the initial phase of the disturbance along the x-axis, the dayside
magnetopause (MP) expands slower than the previous cases of IMF orientations
as a result of the abrupt depression. The size of the MP expands nonlinearly
due to strengthening of its outer boundary by the northward IMF. Also,
during the initial 100 Δ<I>t</I>, the MP shrank down from 13.3 <I>R</I><sub>E</sub>
to ~9.2 <I>R</I><sub>E</sub> before it started expanding, a phenomenon that was
also observed for southern IMF conditions but not during the no IMF case.
As soon as they felt the solar wind depression, cusps widened at high
altitude while dragged in an upright position. For the field's topology,
the reconnection between magnetospheric and magnetosheath fields is clearly
observed in both the northward and southward cusps areas. Also, the tail region
in the northward IMF condition is more confined, in contrast to the fishtail-shape
obtained in the southward IMF case. An X-point is formed in the tail at ~110 <I>R</I><sub>E</sub>
compared to ~103 <I>R</I><sub>E</sub> and ~80 <I>R</I><sub>E</sub> for <I>B</I><sub>z</sub>=0 and
<I>B</I><sub>z</sub><0, respectively. Our findings are consistent with existing reports
from many space observatories (Cluster, Geotail, Themis, etc.) for which
predictions are proposed to test furthermore our simulation technique. |
| first_indexed | 2024-12-12T08:08:39Z |
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| id | doaj.art-d8d804ba7e8e48a0b96ee2865d5c102f |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-12T08:08:39Z |
| publishDate | 2011-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-d8d804ba7e8e48a0b96ee2865d5c102f2022-12-22T00:31:52ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762011-01-0129314610.5194/angeo-29-31-2011Impact of solar wind depression on the dayside magnetosphere under northward interplanetary magnetic fieldS. Baraka0S. Baraka1L. Ben-Jaffel2L. Ben-Jaffel3Center for Theoretical and Applied Physics, Al Aqsa University, Gaza, PalestineTech, Blacksburg, VA 24061, resident at National Institute of Aerospace 100 Exploration Way, Hampton, VA 23666, USAUPMC Paris 06, UMR 7095, Institut d'Astrophysique de Paris, 75014, Paris, FranceCNRS, UMR7095, Institut d'Astrophysique de Paris, 75014, Paris, FranceWe present a follow up study of the sensitivity of the Earth's magnetosphere to solar wind activity using a particles-in-cell model (Baraka and Ben Jaffel, 2007), but here during northward Interplanetary Magnetic Field (IMF). The formation of the magnetospheric cavity and its elongation around the planet is obtained with the classical structure of a magnetosphere with parallel lobes. An impulsive disturbance is then applied to the system by changing the bulk velocity of the solar wind to simulate a decrease in the solar wind dynamic pressure followed by its recovery. In response to the imposed drop in the solar wind velocity, a gap (abrupt depression) in the incoming solar wind plasma appears moving toward the Earth. The gap's size is a ~15 <I>R</I><sub>E</sub> and is comparable to the sizes previously obtained for both <I>B</I><sub>z</sub><0 and <I>B</I><sub>z</sub>=0. During the initial phase of the disturbance along the x-axis, the dayside magnetopause (MP) expands slower than the previous cases of IMF orientations as a result of the abrupt depression. The size of the MP expands nonlinearly due to strengthening of its outer boundary by the northward IMF. Also, during the initial 100 Δ<I>t</I>, the MP shrank down from 13.3 <I>R</I><sub>E</sub> to ~9.2 <I>R</I><sub>E</sub> before it started expanding, a phenomenon that was also observed for southern IMF conditions but not during the no IMF case. As soon as they felt the solar wind depression, cusps widened at high altitude while dragged in an upright position. For the field's topology, the reconnection between magnetospheric and magnetosheath fields is clearly observed in both the northward and southward cusps areas. Also, the tail region in the northward IMF condition is more confined, in contrast to the fishtail-shape obtained in the southward IMF case. An X-point is formed in the tail at ~110 <I>R</I><sub>E</sub> compared to ~103 <I>R</I><sub>E</sub> and ~80 <I>R</I><sub>E</sub> for <I>B</I><sub>z</sub>=0 and <I>B</I><sub>z</sub><0, respectively. Our findings are consistent with existing reports from many space observatories (Cluster, Geotail, Themis, etc.) for which predictions are proposed to test furthermore our simulation technique.https://www.ann-geophys.net/29/31/2011/angeo-29-31-2011.pdf |
| spellingShingle | S. Baraka S. Baraka L. Ben-Jaffel L. Ben-Jaffel Impact of solar wind depression on the dayside magnetosphere under northward interplanetary magnetic field Annales Geophysicae |
| title | Impact of solar wind depression on the dayside magnetosphere under northward interplanetary magnetic field |
| title_full | Impact of solar wind depression on the dayside magnetosphere under northward interplanetary magnetic field |
| title_fullStr | Impact of solar wind depression on the dayside magnetosphere under northward interplanetary magnetic field |
| title_full_unstemmed | Impact of solar wind depression on the dayside magnetosphere under northward interplanetary magnetic field |
| title_short | Impact of solar wind depression on the dayside magnetosphere under northward interplanetary magnetic field |
| title_sort | impact of solar wind depression on the dayside magnetosphere under northward interplanetary magnetic field |
| url | https://www.ann-geophys.net/29/31/2011/angeo-29-31-2011.pdf |
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