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• Ivarsen, Magnus Fagernes; Hoang, Huy Minh; Yang, Lei; Clausen, Lasse Boy Novock; Spicher, Andres & Jin, Yaqi [Show all 10 contributors for this article] (2019). Multineedle Langmuir Probe Operation and Acute Probe Current Susceptibility to Spacecraft Potential. IEEE Transactions on Plasma Science. ISSN 0093-3813. 47(8), p. 3816–3823. doi: 10.1109/TPS.2019.2906377. Full text in Research Archive Show summary

  NorSat-1 was launched on July 14, 2017 as a satellite carrying, among other instruments, the multineedle Langmuir probe (m-NLP), an instrument which, on NorSat-1, is capable of measuring the ionospheric plasma electron density with the high sampling frequency of 1000 Hz. The m-NLP instrument operates by analyzing the current-voltage diagram resulting from the measurements from each individual probe. In principle, the m-NLP operation methodology should be insensitive to spacecraft charging. However, this is not always the case. In this paper, we present an overview of the instrument response to passes into and out of eclipse. When the satellite exits eclipse, we observe a collapse in the collected probe currents. This acute drop is unaccounted for by the theoretical operation of the instrument. We present a statistical analysis of the phenomenon based on several months of NorSat-1 data, and we suggest a plausible reason for the observed drop in the current, namely, spacecraft charging, by solar cell arrays upon eclipse exit. We briefly discuss how satellite orientation and plasma wake affect the current drop. With this paper, we address Langmuir probe current susceptibility to spacecraft potential.

• Wu, J.; Bryant, Mark S; Ridley, CG; Shen, Y; Yang, Lei & Clausen, Lasse Boy Novock [Show all 13 contributors for this article] (2017). A comparison of small-scale magnetic fluctuations in the Region 1 and 2 field-aligned current systems. Journal of Geophysical Research (JGR): Biogeosciences. ISSN 2169-8953. 122(3), p. 3277–3290. doi: 10.1002/2016JA023453. Full text in Research Archive Show summary

  By determining the location and size of the Region 1 (R1) and Region 2 (R2) large‐scale field‐aligned currents (FACs) from Active Magnetosphere and Planetary Electrodynamics Response Experiment data, we are able to study the small‐scale magnetic fluctuations observed by the Swarm satellites embedded within the large‐scale FACs. A statistical comparison of R1 and R2 high‐frequency fluctuations is presented in terms of different solar wind conditions and geomagnetic activities. We find that (1) the amplitude of high‐frequency fluctuations in both R1 and R2 increases as the large‐scale R1 and R2 FACs intensify; (2) high‐frequency fluctuations in R1 peak near dayside dawn and dusk, while those in R2 peak around noon; (3) the location of the largest high‐frequency fluctuations in R1 shifts in local time in response to IMF By, indicating a connection between the R1 fluctuation and the driving solar wind most likely explained by magnetic reconnection; and (4) high‐frequency fluctuations in R2 are enhanced in a small region near local noon and respond clearly to nightside drivers, as characterized by the auroral electrojet index. Our analysis shows that the intensity of R1 and R2 high‐frequency magnetic fluctuations is directly connected to the intensity of FACs, which implies that the magnetic fluctuations are closely related to the magnetospheric processes that drive them. © 2017 American Geophysical Union

• Eriksson, AI; Engelhardt, IAD; Andre, M; Boström, R; Edberg, NJT & Johansson, F. L. [Show all 23 contributors for this article] (2017). Cold and warm electrons at comet 67P/Churyumov-Gerasimenko. Astronomy and Astrophysics (A & A). ISSN 0004-6361. 605. doi: 10.1051/0004-6361/201630159. Full text in Research Archive
• Yang, Lei; Paulsson, Joakim John Paul; Wedlund, Cyril Simon; Odelstad, Elias; Edberg, Niklas & Koenders, C. [Show all 8 contributors for this article] (2016). Observations of high-plasma density region in the inner coma of 67P/Churyumov–Gerasimenko during early activity. Monthly notices of the Royal Astronomical Society. ISSN 0035-8711. 462, p. S33–S44. doi: 10.1093/mnras/stw2046. Full text in Research Archive

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• Miloch, Wojciech Jacek; Yang, Lei; Paulsson, Joakim John Paul; Wedlund, Cyril Simon; Odelstad, Elias & Edberg, Niklas [Show all 8 contributors for this article] (2016). Early Evolution of Comet 67P Studied with the RPC-LAP onboard Rosetta. Full text in Research Archive
• Yang, Lei (2015). Data Analysis of Rosetta Langmuir Probe measurements: first steps. Universitetet i Oslo. Full text in Research Archive

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