Search Publications
Estimating ion escape from unmagnetized planets
Holmstrom, Mats
We propose a new method to estimate ion escape from unmagnetized planets that combines observations and models. Assuming that upstream solar wind conditions are known, a computer model of the interaction between the solar wind and the planet is executed for different ionospheric ion production rates. This results in different amounts of mass loadi…
An investigation into the spectral parameters of ultra-low-frequency (ULF) waves in the polar caps and magnetotail
Nosikova, Nataliya Sergeevna; Yagova, Nadezda Viktorovna; Baddeley, Lisa Jane +2 more
The present case study is focused on fluctuations at ∼ 1.5 mHz observed on open field lines in both of the polar caps in ground-based geomagnetic data and in the electron concentration in the Northern Hemisphere ionosphere. Coherent pulsations with a relatively narrow narrowband-like spectra and a higher fraction of transversal components in the t…
Warm protons at comet 67P/Churyumov-Gerasimenko - implications for the infant bow shock
Nilsson, Hans; Goetz, Charlotte; Gunell, Herbert +4 more
The plasma around comet 67P/Churyumov-Gerasimenko showed remarkable variability throughout the entire Rosetta mission. Plasma boundaries such as the diamagnetic cavity, solar wind ion cavity and infant bow shock separate regions with distinct plasma parameters from each other. Here, we focus on a particular feature in the plasma: warm, slow solar …
Steepening of magnetosonic waves in the inner coma of comet 67P/Churyumov-Gerasimenko
Henri, Pierre; Goetz, Charlotte; Richter, Ingo +7 more
We present a statistical survey of large-amplitude, asymmetric plasma and magnetic field enhancements detected outside the diamagnetic cavity at comet 67P/Churyumov-Gerasimenko from December 2014 to June 2016. Based on the concurrent observations of plasma and magnetic field enhancements, we interpret them to be magnetosonic waves. The aim is to p…
Foreshock cavitons and spontaneous hot flow anomalies: a statistical study with a global hybrid-Vlasov simulation
Blanco-Cano, Xóchitl; Alho, Markku; Johlander, Andreas +10 more
The foreshock located upstream of Earth's bow shock hosts a wide variety of phenomena related to the reflection of solar wind particles from the bow shock and the subsequent formation of ultra-low-frequency (ULF) waves. In this work, we investigate foreshock cavitons, which are transient structures resulting from the non-linear evolution of ULF wa…
Vlasov simulation of electrons in the context of hybrid global models: an eVlasiator approach
Alho, Markku; Johlander, Andreas; Pfau-Kempf, Yann +8 more
Modern investigations of dynamical space plasma systems such as magnetically complicated topologies within the Earth's magnetosphere make great use of supercomputer models as well as spacecraft observations. Space plasma simulations can be used to investigate energy transfer, acceleration, and plasma flows on both global and local scales. Simulati…
Ion acoustic waves near a comet nucleus: Rosetta observations at comet 67P/Churyumov-Gerasimenko
Henri, Pierre; Nilsson, Hans; Goetz, Charlotte +6 more
Ion acoustic waves were observed between 15 and 30 km from the centre of comet 67P/Churyumov-Gerasimenko by the Rosetta spacecraft during its close flyby on 28 March 2015. There are two electron populations: one cold at kBTe≈0.2 eV and one warm at kBTe≈2 eV. The ions are dominated by a cold (a few hundre…
Venus's induced magnetosphere during active solar wind conditions at BepiColombo's Venus 1 flyby
Miyoshi, Yoshizumi; Plaschke, Ferdinand; Futaana, Yoshifumi +23 more
Out of the two Venus flybys that BepiColombo uses as a gravity assist manoeuvre to finally arrive at Mercury, the first took place on 15 October 2020. After passing the bow shock, the spacecraft travelled along the induced magnetotail, crossing it mainly in the YVSO direction. In this paper, the BepiColombo Mercury Planetary Orbiter Mag…
Evidence of the nonstationarity of the terrestrial bow shock from multi-spacecraft observations: methodology, results, and quantitative comparison with particle-in-cell (PIC) simulations
Mazelle, Christian; Lembège, Bertrand
The nonstationarity of the terrestrial bow shock is analyzed in detail from in situ magnetic field measurements issued from the fluxgate magnetometer (FGM) experiment of the Cluster mission. Attention is focused on statistical analysis of quasi-perpendicular supercritical shock crossings. The present analysis stresses for the first time the import…
Dynamics of variable dusk-dawn flow associated with magnetotail current sheet flapping
Grocott, Adrian; Walach, Maria-Theresia; Lane, James H. +1 more
We present Cluster spacecraft observations from 12 October 2006 of convective plasma flows in the Earth's magnetotail. Earthward flow bursts with a dawnward v⊥y component, observed by Cluster 1 (C1), are inconsistent with the duskward flow that might be expected at the pre-midnight location of the spacecraft. Previous observations have …