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Dust sputtering within the inner heliosphere: a modelling study
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-03)
The aim of this study is to investigate how sputtering by impacting solar wind particles influence the lifetime of dust particles in the inner heliosphere near the Sun.<p><p>
We consider three typical dust materials: silicate, Fe<sub>0.4</sub>Mg<sub>0.6</sub>O and carbon and describe their sputtering yields based on atomic yields given by the Stopping and Range of Ions in Matter (SRIM) package. ...
A comparison of contact charging and impact ionization in low-velocity impacts: implications for dust detection in space
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-15)
We investigate the generation of charge due to collision between projectiles with sizes below ∼1 µm and metal surfaces at speeds ∼0.1 to 10 km s−1. This corresponds to speeds above the elastic limit and well below speeds where volume ionization can occur. Impact charge production at these low to intermediate speeds has traditionally been described by invoking the theory of shock wave ionization. By ...
Dynamics of nanodust in the vicinity of a stellar corona: Effect of plasma corotation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-24)
Context - In the vicinity of the Sun or other stars, the motion of the coronal and stellar wind plasma must include some amount of
corotation, which could affect the dynamics of charged dust particles. In the case of the Sun, this region is now investigated in situ by
the Parker Solar Probe. Charged dust particles coming from the vicinity of the Sun can also reach, and possibly be detected by, ...
The influence of surface charge on the coalescence of ice and dust particles in the mesosphere
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-09)
Agglomeration of charged ice and dust particles in the mesosphere and lower thermosphere is studied using a classical electrostatic approach, which is extended to capture the induced polarisation of surface charge. Collision outcomes are predicted whilst varying the particle size, charge, dielectric constant, relative kinetic energy, collision geometry and the coefficient of restitution. In addition ...
A comparison of contact charging and impact ionization in low-velocity impacts: implications for dust detection in space
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-15)
We investigate the generation of charge due to collision between projectiles with sizes below ∼1 µm and metal surfaces at speeds ∼0.1 to 10 km s<sup>−1</sup>. This corresponds to speeds above the elastic limit and well below speeds where volume ionization can occur. Impact charge production at these low to intermediate speeds has traditionally been described by invoking the theory of shock wave ...
Investigation of Polar Mesospheric Summer Echoes Using Linear Discriminant Analysis
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-02)
Polar Mesospheric Summer Echoes (PMSE) are distinct radar echoes from the Earth’s upper atmosphere between 80 to 90 km altitude that form in layers typically extending only a few km in altitude and often with a wavy structure. The structure is linked to the formation process, which at present is not yet fully understood. Image analysis of PMSE data can help carry out systematic studies to characterize ...
Cometary plasma science: Open science questions for future space missions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-07)
Comets hold the key to the understanding of our Solar System, its formation and its evolution, and to the fundamental plasma processes at work both in it and beyond it. A comet nucleus emits gas as it is heated by the sunlight. The gas forms the coma, where it is ionised, becomes a plasma, and eventually interacts with the solar wind. Besides these neutral and ionised gases, the coma also contains ...
Dust observations from Parker Solar Probe: Dust ejection from the inner Solar System
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-02)
Context. The FIELDS instrument onboard Parker Solar Probe (PSP) observes dust impacts on the spacecraft. The derived dust flux
rates suggest that the particles originate from the vicinities of the Sun and are ejected by radiation pressure. Radiation pressure typically
ejects particles of several 100 nm and smaller, which are also affected by the electromagnetic force.<p>
Aims. We aim to understand ...
Formation of an additional density peak in the bottom side of the sodium layer associated with the passage of multiple mesospheric frontal systems
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-18)
We present a detailed investigation of the formation of an additional sodium density peak at altitudes of 79–85 km below the main peak of the sodium layer based on sodium lidar and airglow imager measurements made at Ramfjordmoen near Tromsø, Norway, on the night of 19 December 2014. The airglow imager observations of OH emissions revealed four passing frontal systems that resembled mesospheric ...
Modelling the influence of meteoric smoke particles on artificial heating in the D-region
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-17)
We investigate if the presence of meteoric smoke particles (MSPs) influences the electron temperature during artificial heating in the D-region. By transferring the energy of powerful high-frequency radio waves into thermal energy of electrons, artificial heating increases the electron temperature. Artificial heating depends on the height variation of electron density. The presence of MSPs can ...