A New Result in Form of Finite Triple Sums for a Series from Ramanujan’s Notebooks

Autor: Erik Vigren, Andreas Dieckmann

Publikováno v: Symmetry, Vol 14, Iss 6, p 1090 (2022)

We consider a function g(r,x,u) with x,u∈ℂ and r∈ℕ, which, over a symmetric domain, equals the sum of an infinite series as noted in the 16th Entry of Chapter 3 in Ramanujan’s second notebook. The function attracted new attention since it w

Externí odkaz: https://doaj.org/article/5d9a09a98c544ce8816b20aacccc4fef

Deriving mixing ratios of heavier neutral species in Saturn's ionosphere from light ion measurements and helium chemistry

Autor: Joshua Dreyer, Erik Vigren, Fredrik L. Johansson, J. Hunter Waite

Helium ions, He+, react only slowly with molecular hydrogen. A consequence of this is that He+ ions produced by, for example, photoionization of He in H2-dominated ionospheres, such as those of Jupiter and Saturn, can have principal loss mechanisms o

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::b2e63fc6ad9eac2635778efb828ad7ed
https://doi.org/10.5194/egusphere-egu23-14642

Simple Solutions of Lattice Sums for Electric Fields Due to Infinitely Many Parallel Line Charges

Autor: Erik Vigren, Andreas Dieckmann

Publikováno v: Symmetry, Vol 12, Iss 6, p 1040 (2020)

We present surprisingly simple closed-form solutions for electric fields and electric potentials at arbitrary position ( x , y ) within a plane crossed by infinitely long line charges at regularly repeating positions using angular or elliptic functio

Externí odkaz: https://doaj.org/article/de8bd71a3adf430cb325c0399e426b36

Cometary plasma science

Autor: L. Andersson, Ivana Kolmasova, Elias Odelstad, J. De Keyser, M. Galand, Herbert Gunell, Yasong Ge, Hans Nilsson, Tomas Karlsson, Ferdinand Plaschke, Markku Alho, Beatriz Sánchez-Cano, Pierre Henri, Satoshi Kasahara, Kristie LLera, Jan Deca, C. Simon Wedlund, Anders Eriksson, Charlotte Goetz, Karl-Heinz Glassmeier, Martin Volwerk, H. Madanian, Nicolas André, Rajkumar Hajra, Christian Mazelle, Arnaud Beth, Ingrid Mann, Erik Vigren, Martin Rubin, Colin Snodgrass

Publikováno v: Goetz, C, Gunell, H, Volwerk, M, Beth, A, Eriksson, A, Galand, M, Henri, P, Nilsson, H, Wedlund, C S, Alho, M, Andersson, L, Andre, N, De Keyser, J, Deca, J, Ge, Y, Glassmeier, K H, Hajra, R, Karlsson, T, Kasahara, S, Kolmasova, I, Lera, K L, Madanian, H, Mann, I, Mazelle, C, Odelstad, E, Plaschke, F, Rubin, M, Sanchez-Cano, B, Snodgrass, C & Vigren, E 2021, ' Cometary plasma science Open science questions for future space missions ', Experimental Astronomy, vol. 104 . https://doi.org/10.1007/s10686-021-09783-z

Funding Information: C. G. is supported by an ESA Research Fellowship. H. G. acknowledges support by the Swedish National Space Agency grant 108/18. B. S.-C. acknowledges support through UK-STFC grant ST/S000429/1. French co-authors acknowledge the s

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::da0608d78cdf59ecd0c4833d0b0db4c6
https://doi.org/10.1007/s10686-021-09783-z

Radial distribution of plasma at comet 67P and implications for cometary flyby missions

Autor: Niklas J. T. Edberg, Fredrik Leffe Johansson, Anders I. Eriksson, Erik Vigren, Pierre Henri, Johan De Keyser

The Rosetta spacecraft followed comet 67P/Churyumov-Gerasimenko (67P) for more than two years, at slow walking pace (about 1 m/s) within 1500 km from the nucleus. During one of the radial movements of the S/C in the early phase of the mission the rad

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::988d2b7ca2391c7619df8bfeb0782559
https://doi.org/10.5194/epsc2022-631