Patrick Guio

The structure of Jupiter's magnetosphere reflects the combined effects of a strong intrinsic field and an extended hinged current sheet whose morphology varies with solar wind forcing. We present a study of Jupiter's magnetodisc that combines the UCL‐AGA magnetodisc code with Khurana's generalized, hinged current sheet models (1992/2022) to fit Juno MAG data from orbits PJ6–PJ12 and PJ34 using a “rolling‐window” approach. Periods of relative stability (“quiescent” magnetosphere) are identified during each pass, reducing the impact of transient solar‐wind and reconfiguration events. The underlying magnetospheric parameters are then determined and current sheet morphology constrained. Estimated magnetopause distances are also obtained and compared to the results obtained by Joy et al. (2002, https://doi.org/10.1029/2001ja009146 ), showing most probable subsolar standoff distances between 46 and 64 and results consistent with dawn‐dusk asymmetry and/or a cushion region along the dusk flank. This approach reveals substantial per‐perijove magnetospheric and current sheet geometry variability, as well as capturing changes in hot‐plasma content and effective magnetodisc radius within a single pass. Correlations between model parameters link extended magnetospheres to larger magnetic field sweepback onset distances, with weaker negative trends linking magnetospheric compression with the Alfvén wave propagation speed and hot plasma content with the distance at which hinging becomes significant. Finally, both MDISC + Khurana model variants are shown to match, and often outperform, the optimized Connerney (2020) baseline current disc model across most perijoves analyzed.

In the ionosphere, a sustained population of suprathermal electrons arises due to photoionization or electron precipitation. The presence of such a population enhances the scattered power in the plasma line spectrum, thus making it possible to detect them. Plasma line measurements improve the accuracy of electron density and temperature estimates. We investigate plasma line enhancements in EISCAT Tromsø UHF radar observations, using two image processing methodologies for detection: a supervised image morphological processing technique and an unsupervised connected component analysis. The supervised methodology detects more plasma lines, demonstrating higher sensitivity. We determine the times and altitudes with enhancements and model the spectrum with a Gaussian function. The radar beam points in the field-aligned direction for 25 % of the total observational time, is directed east for another 25 % and is oriented in the vertical direction for the remaining 50 %. Plasma lines are detected 26 % of the time when the radar is pointed in the field-aligned direction, 5 % of the time in the east direction and 5 % of the time in the vertical direction. Most plasma lines are detected around the F-region altitude where the electron density is maximum, typically between 230–260 km, with a simultaneous increase in the electron density estimates from the ion line. Plasma line intensity is maximum around noon. It decreases as the aspect angle increases. Both detection methodologies' advantages and disadvantages are discussed, and plasma line intensity variations are analyzed as a function of altitude, aspect angle and phase energy.

In the ionosphere, a sustained population of suprathermal electrons arises due to photoionization or electron precipitation. The presence of such a population enhances the scattered power in the plasma line spectrum, thus making it possible to detect them. Plasma line measurements improve the accuracy of electron density and temperature estimates. We investigate plasma line enhancements in EISCAT Tromsø UHF radar observations, using two image processing methodologies for detection: a supervised image morphological processing technique and an unsupervised connected component analysis. The supervised methodology detects more plasma lines, demonstrating higher sensitivity. We determine the times and altitudes with enhancements and model the spectrum with a Gaussian function. The radar beam points in the field-aligned direction for 25 % of the total observational time, is directed east for another 25 % and is oriented in the vertical direction for the remaining 50 %. Plasma lines are detected 26 % of the time when the radar is pointed in the field-aligned direction, 5 % of the time in the east direction and 5 % of the time in the vertical direction. Most plasma lines are detected around the F-region altitude where the electron density is maximum, typically between 230–260 km, with a simultaneous increase in the electron density estimates from the ion line. Plasma line intensity is maximum around noon. It decreases as the aspect angle increases. Both detection methodologies' advantages and disadvantages are discussed, and plasma line intensity variations are analyzed as a function of altitude, aspect angle and phase energy.

In the ionosphere, a sustained population of suprathermal electrons arises due to photoionization or electron precipitation. The presence of such a population enhances the scattered power in the plasma line spectrum, thus making it possible to detect them. Plasma line measurements improve the accuracy of electron density and temperature estimates. We investigate plasma line enhancements in EISCAT Tromsø UHF radar observations, using two image processing methodologies for detection: a supervised image morphological processing technique and an unsupervised connected component analysis. The supervised methodology detects more plasma lines, demonstrating higher sensitivity. We determine the times and altitudes with enhancements and model the spectrum with a Gaussian function. The radar beam points in the field-aligned direction for 25 % of the total observational time, is directed east for another 25 % and is oriented in the vertical direction for the remaining 50 %. Plasma lines are detected 26 % of the time when the radar is pointed in the field-aligned direction, 5 % of the time in the east direction and 5 % of the time in the vertical direction. Most plasma lines are detected around the F-region altitude where the electron density is maximum, typically between 230–260 km, with a simultaneous increase in the electron density estimates from the ion line. Plasma line intensity is maximum around noon. It decreases as the aspect angle increases. Both detection methodologies' advantages and disadvantages are discussed, and plasma line intensity variations are analyzed as a function of altitude, aspect angle and phase energy.

In Paranicas et al. (2020), https://doi.org/10.1029/2020ja028299 , we reported on a method to estimate the inflow speed of interchange injections in Saturn's magnetosphere. The procedure relies on phase space density conservation and mapping and an estimate of the size of the flux decrease along one edge of the injection. Here we describe modifications to the method. We have applied our new technique to an existing list of injections, presenting only those injections with inflow speeds greater than 20 km/s, defined as “fast” injections here. We find at least 20% of the events from the list can be considered fast. Faster injections are more effective in energizing charged particles as the injection moves planetward. This is because shorter transit time limits the number of particles that can drift longitudinally out of the injection.

In the ionosphere, a sustained population of suprathermal electrons arises due to photoionization or electron precipitation. The presence of such a population enhances the scattered power in the plasma line spectrum, thus making it possible to detect them. Plasma line measurements improve the accuracy of electron density and temperature estimates. We investigate plasma line enhancements in EISCAT Tromsø UHF radar observations, using two image processing methodologies for detection: a supervised image morphological processing technique and an unsupervised connected component analysis. The supervised methodology detects more plasma lines, demonstrating higher sensitivity. We determine the times and altitudes with enhancements and model the spectrum with a Gaussian function. The radar beam points in the field-aligned direction for 25 % of the total observational time, is directed east for another 25 % and is oriented in the vertical direction for the remaining 50 %. Plasma lines are detected 26 % of the time when the radar is pointed in the field-aligned direction, 5 % of the time in the east direction and 5 % of the time in the vertical direction. Most plasma lines are detected around the F-region altitude where the electron density is maximum, typically between 230–260 km, with a simultaneous increase in the electron density estimates from the ion line. Plasma line intensity is maximum around noon. It decreases as the aspect angle increases. Both detection methodologies' advantages and disadvantages are discussed, and plasma line intensity variations are analyzed as a function of altitude, aspect angle and phase energy.

In the ionosphere, a sustained population of suprathermal electrons arises due to photoionization or electron precipitation. The presence of such a population enhances the scattered power in the plasma line spectrum, thus making it possible to detect them. Plasma line measurements improve the accuracy of electron density and temperature estimates. We investigate plasma line enhancements in EISCAT Tromsø UHF radar observations, using two image processing methodologies for detection: a supervised image morphological processing technique and an unsupervised connected component analysis. The supervised methodology detects more plasma lines, demonstrating higher sensitivity. We determine the times and altitudes with enhancements and model the spectrum with a Gaussian function. The radar beam points in the field-aligned direction for 25 % of the total observational time, is directed east for another 25 % and is oriented in the vertical direction for the remaining 50 %. Plasma lines are detected 26 % of the time when the radar is pointed in the field-aligned direction, 5 % of the time in the east direction and 5 % of the time in the vertical direction. Most plasma lines are detected around the F-region altitude where the electron density is maximum, typically between 230–260 km, with a simultaneous increase in the electron density estimates from the ion line. Plasma line intensity is maximum around noon. It decreases as the aspect angle increases. Both detection methodologies' advantages and disadvantages are discussed, and plasma line intensity variations are analyzed as a function of altitude, aspect angle and phase energy.

In the ionosphere, a sustained population of suprathermal electrons arises due to photoionization or electron precipitation. The presence of such a population enhances the scattered power in the plasma line spectrum, thus making it possible to detect them. Plasma line measurements improve the accuracy of electron density and temperature estimates. We investigate plasma line enhancements in EISCAT Tromsø UHF radar observations, using two image processing methodologies for detection: a supervised image morphological processing technique and an unsupervised connected component analysis. The supervised methodology detects more plasma lines, demonstrating higher sensitivity. We determine the times and altitudes with enhancements and model the spectrum with a Gaussian function. The radar beam points in the field-aligned direction for 25 % of the total observational time, is directed east for another 25 % and is oriented in the vertical direction for the remaining 50 %. Plasma lines are detected 26 % of the time when the radar is pointed in the field-aligned direction, 5 % of the time in the east direction and 5 % of the time in the vertical direction. Most plasma lines are detected around the F-region altitude where the electron density is maximum, typically between 230–260 km, with a simultaneous increase in the electron density estimates from the ion line. Plasma line intensity is maximum around noon. It decreases as the aspect angle increases. Both detection methodologies' advantages and disadvantages are discussed, and plasma line intensity variations are analyzed as a function of altitude, aspect angle and phase energy.

In the Incoherent Scatter Radar (ISR) spectrum, we observe a large amount of scattered power at frequencies corresponding to plasma electrostatic modes with wavenumber imposed by the radar. The commonly occurring resonant frequencies are ion and plasma lines. Ion lines are signatures of ion-acoustic waves travelling towards and away from the radar and are observable all the time. Plasma lines are signatures of high-frequency electrostatic waves and are observable when enhanced above the thermal level by a suprathermal electron population. In this work, we assume a Maxwellian thermal population together with a suprathermal population derived from the electron transport code Aeroplanets that calculates the angular electron flux. We provide the numerical electron velocity distribution function as an input to the Arbitrary Linear Plasma Solver (ALPS) to numerically solve the linear Vlasov-Maxwell dispersion relation and estimate the resonance frequency at angles to the magnetic field. The linear resonance frequency calculated from ALPS is then compared to the resonance frequency estimated from ISR plasma line measurements.