A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Magnetosheath Jets Over Solar Cycle 24: An Empirical Model
Tekijät: Vuorinen Laura, LaMoury Adrian T., Hietala Heli, Koller Florian
Kustantaja: AMER GEOPHYSICAL UNION
Julkaisuvuosi: 2023
Journal: Journal of Geophysical Research: Space Physics
Tietokannassa oleva lehden nimi: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
Lehden akronyymi: J GEOPHYS RES-SPACE
Artikkelin numero: e2023JA031493
Vuosikerta: 128
Numero: 8
Sivujen määrä: 12
ISSN: 2169-9380
eISSN: 2169-9402
DOI: https://doi.org/10.1029/2023JA031493
Verkko-osoite: https://doi.org/10.1029/2023JA031493
Rinnakkaistallenteen osoite: https://research.utu.fi/converis/portal/detail/Publication/180691945
Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft have been sampling the subsolar magnetosheath since the first dayside science phase in 2008, and we finally have observations over a solar cycle. However, we show that the solar wind coverage during these magnetosheath intervals is not always consistent with the solar wind conditions throughout the same year. This has implications for studying phenomena whose occurrence depends strongly on solar wind parameters. We demonstrate this with magnetosheath jets-flows of enhanced earthward dynamic pressure in the magnetosheath. Jets emerge from the bow shock, and some of them can go on and collide into the magnetopause. Their occurrence is highly linked to solar wind conditions, particularly the orientation of the interplanetary magnetic field, as jets are mostly observed downstream of the quasi-parallel shock. We study the yearly occurrence rates of jets recorded by THEMIS over solar cycle 24 (2008-2019) and find that they are biased due to differences in spacecraft orbits and uneven sampling of solar wind conditions during the different years. Thus, we instead use the THEMIS observations and their corresponding solar wind conditions to develop a model of how jet occurrence varies as a function of solar wind conditions. We then use OMNI data of the whole solar cycle to estimate the unbiased yearly jet occurrence rates. For comparison, we also estimate jet occurrence rates during solar cycle 23 (1996-2008). Our results suggest that there is no strong solar cycle dependency in jet formation.
Ladattava julkaisu This is an electronic reprint of the original article. |  |
