Zobrazeno 1 - 10
of 12
pro vyhledávání: '"Heikki Vanhamaki"'
Autor:
Michael Madelaire, Karl Laundal, Spencer Hatch, Heikki Vanhamäki, Jone Reistad, Anders Ohma, Viacheslav Merkin, Dong Lin
Publikováno v:
Geophysical Research Letters, Vol 51, Iss 8, Pp n/a-n/a (2024)
Abstract The ionospheric convection electric field is often assumed to be a potential field. This assumption is not always valid, especially when the ionosphere changes on short time scales T≲5 min. We present a technique for estimating the inducti
Externí odkaz:
https://doaj.org/article/1eb3777876704ce8adb5f4e1ef943e7f
Publikováno v:
Scientific Reports, Vol 13, Iss 1, Pp 1-6 (2023)
Abstract A digital society is fragile and vulnerable to space-originated electromagnetic disturbances. Global geomagnetic conditions have been actively monitored since the invention of the magnetometer in 1833. However, regional changes in the magnet
Externí odkaz:
https://doaj.org/article/09e2bb59f8254ed282f0f7656000ce54
Autor:
Shin-ichiro Oyama, Anita Aikio, Takeshi Sakanoi, Keisuke Hosokawa, Heikki Vanhamäki, Lei Cai, Ilkka Virtanen, Marcus Pedersen, Kazuo Shiokawa, Atsuki Shinbori, Nozomu Nishitani, Yasunobu Ogawa
Publikováno v:
Earth, Planets and Space, Vol 75, Iss 1, Pp 1-13 (2023)
Abstract Ion drag associated with the ionospheric plasma convection plays an important role in the high-latitude thermospheric dynamics, yet changes in the thermospheric wind with geomagnetic activity are not fully understood. We performed a statisti
Externí odkaz:
https://doaj.org/article/12474185579b450188a60e5cd3dcdc32
Autor:
Shin-ichiro Oyama, Heikki Vanhamäki, Lei Cai, Anita Aikio, Michael Rietveld, Yasunobu Ogawa, Tero Raita, Mirjam Kellinsalmi, Kirsti Kauristie, Boris Kozelov, Atsuki Shinbori, Kazuo Shiokawa, Takuo T. Tsuda, Takeshi Sakanoi
Publikováno v:
Earth, Planets and Space, Vol 74, Iss 1, Pp 1-17 (2022)
Abstract The thermospheric wind response to a sudden westward turning of the ion velocity at a high latitude was studied by analyzing data obtained with a Fabry–Perot interferometer (FPI; 630 nm), Dynasonde, and Swarm A & C satellites during a conj
Externí odkaz:
https://doaj.org/article/f1c0d9a93a554d81ae5f7ef5e41bf4bf
Autor:
Lei Cai, Anita Aikio, Anita Kullen, Yue Deng, Yongliang Zhang, Shun-Rong Zhang, Ilkka Virtanen, Heikki Vanhamäki
Publikováno v:
Frontiers in Astronomy and Space Sciences, Vol 9 (2022)
In the space physics community, processing and combining observational and modeling data from various sources is a demanding task because they often have different formats and use different coordinate systems. The Python package GeospaceLAB has been
Externí odkaz:
https://doaj.org/article/7673320d222b4ab3b038f8bfff90fc5c
Autor:
Timo Pitkänen, Anita Kullen, Lei Cai, Jong-Sun Park, Heikki Vanhamäki, Maria Hamrin, Anita T. Aikio, G. Siung Chong, Alexandre De Spiegeleer, Quanqi Shi
Publikováno v:
Geoscience Letters, Vol 8, Iss 1, Pp 1-11 (2021)
Abstract Evidence suggests that a non-zero dawn–dusk interplanetary magnetic field (IMF $$B_y$$ B y ) can cause a rotation of the cross-tail current sheet/neutral sheet around its axis aligned with the Sun–Earth line in Earth’s magnetotail. We
Externí odkaz:
https://doaj.org/article/7b7b694f0fed4936a2bdd315bccd2850
Publikováno v:
Earth, Planets and Space, Vol 72, Iss 1, Pp 1-14 (2020)
Abstract The technique of spherical elementary current systems (SECS) is a powerful way to determine ionospheric and field-aligned currents (FAC) from magnetic field measurements made by low-Earth-orbiting satellites, possibly in combination with mag
Externí odkaz:
https://doaj.org/article/70129624aebe472da2ada588a186e54e
Autor:
Gopika Prasannakumara Pillai Geethakumari, Anita Aikio, Lei Cai, Heikki Vanhamaki, Marcus Pedersen, Anthea J. Coster, Aurelie Marchaudon, Pierre-Louis Blelly, Veronika Haberele, Astrid Maute, Nada Ellahouny, Ilkka Virtanen, Johannes Norberg, Shin Oyama, Alexander Kozlovsky, Maxime Grandin
Solar wind interactions with the Earth’s magnetosphere cause geomagnetic storms and thereby induce ionospheric storms. This study investigates the spatio-temporal evolution of the ionospheric Total Electron Content (TEC) during a moderate but long
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::dd68dc0b9b8b5131e4b92c33f89f4312
https://doi.org/10.5194/egusphere-egu23-9293
https://doi.org/10.5194/egusphere-egu23-9293
Autor:
Gopika Prasannakumara Pillai Geethakumari, Anita Aikio, Lei Cai, Heikki Vanhamaki, Marcus Pedersen, Anthea Coster, Aurelie Marchaudon, Pierre-Louis Blelly, Veronika Haberle, Astrid Maute, Nada Ellahouny, Ilkka Virtanen, Johannes Norberg, Shin-Ichiro Soyama, Maxime Grandin
Magnetic storms are caused by the interactions between the solar wind and the Earth’s magnetosphere. Many studies have been carried out for strong magnetic storms. However, moderate or weak storms and their impacts on the ionosphere are less explor
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::ebaac2305424a833775b357b52b615b9
https://doi.org/10.5194/egusphere-egu22-8194
https://doi.org/10.5194/egusphere-egu22-8194
Autor:
Shin-ichiro, Oyama, Anita, Aikio, Mark, Conde, Heikki, Vanhamaki, Ilkka, Virtanen, Thomas, Ulich, Urban, Brondstrom, Pekka, Verronen, Monika, Szelag, Niilo, Kalakoski, Lassi, Roininen, Sari, Lasanen, Abiyot, Workayehu, Kazuo, Shiokawa, Xu, Heqiucen, Mamoru, Ishii, Masafumi, Hirahara, Takeshi, Sakanoi, Masato, Kagitani, Juha, Sorri, Tomi, Teppo
The Tenth Symposium on Polar Science/Ordinary sessions: [OS] Space and upper atmospheric sciences, Wed. 4 Dec. / Institute of Statistics and Mathematics (ISM) Seminar room 2 (D304) (3rd floor)
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=jairo_______::320d6994d4c71aadcfed0c216a8dc5f9
http://id.nii.ac.jp/1291/00015752/
http://id.nii.ac.jp/1291/00015752/