jjpaulss

• Paulsson, Joakim John Paul; Miyake, Y.; Miloch, Wojciech Jacek & Usui, H. (2019). Effects of booms of sounding rockets in flowing plasmas. Physics of Plasmas. ISSN 1070-664X. 26(3). doi: 10.1063/1.5051414. Fulltekst i vitenarkiv Vis sammendrag

  Effects of booms of a sounding rocket on rocket charging and on the local plasma conditions are studied with numerical and analytical models accounting for flowing, ionospheric plasmas. Simulations are carried out with a first principles self-consistent Particle-In-Cell numerical code. It is shown that the booms can affect the charging of the payload and disturb the local plasma to a high degree. The boom-to-plasma potential, which varies with the position due to the convective electric field, can lead to significantly different currents, in particular electron currents, to the booms on either side of the rocket. The analytical models for the collected currents considered in this study show good agreement with the simulations. The potential difference between the plasma and the rocket can electrostatically focus the ions to create regions of enhanced ion density downstream of the rocket and can lead to an asymmetric wake. It is shown that ion focusing can be asymmetric between the booms due to the potential gradient. These effects can have implications for instrument placements and data analysis.

• Paulsson, Joakim John Paul; Spicher, Andres; Clausen, Lasse Boy Novock; Moen, Jøran Idar & Miloch, Wojciech Jacek (2018). Wake Potential and Wake Effects on the Ionospheric Plasma Density Measurements With Sounding Rockets. Journal of Geophysical Research (JGR): Space Physics. ISSN 2169-9380. 123(11), s. 9711–9725. doi: 10.1029/2017JA025004. Fulltekst i vitenarkiv Vis sammendrag

  A new method is developed to systematically study variations in the electrostatic potential around a spinning spacecraft in flowing plasma. We argue that the main modulation of this potential is due to wake leading to different depletions in electron and ion densities. This wake potential can be calculated with the help of electric currents measured by Langmuir probes mounted on a boom system and the assumption of Boltzmann‐distributed electrons. The wake position is determined with the electric field measurements. We apply this method to data from the Investigation of Cusp Irregularities 3 ionospheric sounding rocket and find the observed wake to be larger than expected from the flow velocity and the Mach cone formation, which can be explained by the presence of booms. By using the wake potential to filter the rocket data, we show that this method is robust during highly dynamic plasma conditions and that it can be used to improve the quality of plasma density measurements and reduce the wake effects.

• Johansson, Fredrik; Odelstad, E; Paulsson, Joakim John Paul; Harang, Sigve Smedsrud; Eriksson, AI & Mannel, Thurid [Vis alle 13 forfattere av denne artikkelen] (2017). Rosetta photoelectron emission and solar ultraviolet flux at comet 67P. Monthly notices of the Royal Astronomical Society. ISSN 0035-8711. 469, s. S626–S635. doi: 10.1093/mnras/stx2369. Fulltekst i vitenarkiv
• Darian, Diako; Marholm, Sigvald; Paulsson, Joakim John Paul; Miyake, Y.; Usui, H. & Mortensen, Mikael [Vis alle 7 forfattere av denne artikkelen] (2017). Numerical simulations of a sounding rocket in ionospheric plasma: Effects of magnetic field on the wake formation and rocket potential. Journal of Geophysical Research (JGR): Biogeosciences. ISSN 2169-8953. 122(9), s. 9603–9621. doi: 10.1002/2017JA024284. Fulltekst i vitenarkiv Vis sammendrag

  The charging of a sounding rocket in subsonic and supersonic plasma flows with external magnetic field is studied with numerical particle‐in‐cell (PIC) simulations. A weakly magnetized plasma regime is considered that corresponds to the ionospheric F2 layer, with electrons being strongly magnetized, while the magnetization of ions is weak. It is demonstrated that the magnetic field orientation influences the floating potential of the rocket and that with increasing angle between the rocket axis and the magnetic field direction the rocket potential becomes less negative. External magnetic field gives rise to asymmetric wake downstream of the rocket. The simulated wake in the potential and density may extend as far as 30 electron Debye lengths; thus, it is important to account for these plasma perturbations when analyzing in situ measurements. A qualitative agreement between simulation results and the actual measurements with a sounding rocket is also shown. © 2017 American Geophysical Union

• Eriksson, AI; Engelhardt, IAD; Andre, M; Boström, R; Edberg, NJT & Johansson, F. L. [Vis alle 23 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Yang, Lei; Paulsson, Joakim John Paul; Wedlund, Cyril Simon; Odelstad, Elias; Edberg, Niklas & Koenders, C. [Vis alle 8 forfattere av denne artikkelen] (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, s. S33–S44. doi: 10.1093/mnras/stw2046. Fulltekst i vitenarkiv

Se alle arbeider i NVA

• Miloch, Wojciech Jacek; Yang, Lei; Paulsson, Joakim John Paul; Wedlund, Cyril Simon; Odelstad, Elias & Edberg, Niklas [Vis alle 8 forfattere av denne artikkelen] (2016). Early Evolution of Comet 67P Studied with the RPC-LAP onboard Rosetta. Fulltekst i vitenarkiv

Se alle arbeider i NVA