Nickolay Ivchenko

• PhD
• University Lector at KTH Royal Institute of Technology

The MATS (Mesosphere, Airglow/Aerosol, Tomography & Spectroscopy) satellite was launched in November 2022 and began collecting scientific measurements of the Mesosphere and Lower Thermosphere (MLT) in early 2023. The satellite utilises a multichannel limb-viewing instrument designed to gather images across six distinct spectral bands, each selected...

MATS (Mesospheric Airglow/Aerosol Tomography and Spectroscopy) is a Swedish satellite mission designed to investigate atmospheric gravity waves. In order to observe wave patterns MATS observes structures in the O2 atmospheric band airglow (light emitted by oxygen molecules in the Mesosphere and Lower Thermosphere), as well as structures in noctiluc...

The Small Payloads for Investigation of Disturbances in Electrojet by Rockets 2 (SPIDER‐2) sounding rocket was launched from Esrange, Sweden, on the 19th of February 2020 at 23:14 UT. It traversed a pulsating aurora event, deploying eight free falling units which provided in situ multi‐point measurements of the electric field, magnetic field and pl...

This study focuses on the poorly known effect of polar cap patches (PCPs) on the ion‐neutral coupling in the F‐region. The PCPs were identified by total electron content measurements from the Global Navigation Satellite System (GNSS) and the ionospheric parameters from the Defense Meteorological Satellite Program spacecraft. The EISCAT incoherent s...

In situ plasma measurements as well as remote mapping of energetic neutral atoms around Jupiter provide indirect evidence that an enhancement of neutral gas is present near the orbit of the moon Europa. Simulations suggest that such a neutral gas torus can be sustained by escape from Europa’s atmosphere and consists primarily of molecular hydrogen,...

In-situ plasma measurements as well as remote mapping of energetic neutral atoms around Jupiter provide indirect evidence that an enhancement of neutral gas is present near the orbit of the moon Europa. Simulations suggest that such a neutral gas torus can be sustained by escape from Europa's atmosphere and consists primarily of molecular hydrogen,...

The lower thermosphere-ionosphere (LTI) is a key transition region between Earth’s atmosphere and space. Interactions between ions and neutrals maximize within the LTI and in particular at altitudes from 100 to 200 km, which is the least visited region of the near-Earth environment. The lack of in situ co-temporal and co-spatial measurements of all...

Daedalus MASE (Mission Assessment through Simulation Exercise) is an open-source package of scientific analysis tools aimed at research in the Lower Thermosphere-Ionosphere (LTI). It was created with the purpose to assess the performance and demonstrate closure of the mission objectives of Daedalus, a mission concept targeting to perform in-situ me...

In the White Paper, submitted in response to the European Space Agency (ESA) Voyage 2050 Call, we present the importance of advancing our knowledge of plasma-neutral gas interactions, and of deepening our understanding of the partially ionized environments that are ubiquitous in the upper atmospheres of planets and moons, and elsewhere in space. In...

Fragmented aurora-like emissions (FAEs) are small (few kilometres) optical structures which have been observed close to the poleward boundary of the aurora from the high-latitude location of Svalbard (magnetic latitude 75.3 ∘N). The FAEs are only visible in certain emissions, and their shape has no magnetic-field-aligned component, suggesting that...

Ganymede’s atmosphere is produced by charged particle sputtering and sublimation of its icy surface. Previous far-ultraviolet observations of the O i 1,356 Å and O i 1,304 Å oxygen emissions were used to infer sputtered molecular oxygen (O2) as an atmospheric constituent, but an expected sublimated water (H2O) component remained undetected. Here we...

Energetic particle precipitation (EPP) has the potential to change the neutral atmospheric temperature in the mesopause region. However, recent results are inconsistent, leaving the mechanism and the actual effect still unresolved. In this study we have searched for electron precipitation events and investigated a possible correlation between D-reg...

The Small Payloads for Investigation of Disturbances in Electrojet by Rockets (SPIDER) sounding rocket was launched on February 2nd, 2016 (21:09 UT), deploying 10 free falling units (FFUs) inside a westward traveling auroral surge. Each FFUs deployed spherical electric field and Langmuir probes on wire‐booms, providing in situ multi‐point recording...

Ganymede's atmosphere is produced by charged particle sputtering and sublimation of its icy surface. Previous far-ultraviolet observations of the OI1356-A and OI1304-A oxygen emissions were used to derive sputtered molecular oxygen (O$_2$) as an atmospheric constituent but an expected sublimated water (H$_2$O) component remained undetected. Here we...

The lower-thermosphere–ionosphere (LTI) system consists of the upper atmosphere and the lower part of the ionosphere and as such comprises a complex system coupled to both the atmosphere below and space above. The atmospheric part of the LTI is dominated by laws of continuum fluid dynamics and chemistry, while the ionosphere is a plasma system cont...

Fragmented Aurora-like Emissions (FAEs) are small (few km) optical structures which have been observed close to the poleward boundary of the aurora from the high-latitude location of Svalbard (magnetic latitude 75.3 ° N). The FAEs are only visible in certain emissions and their shape has no magnetic-field aligned component, suggesting that they are...

We report both decreasing and increasing trends in the patch sizes during pulsating aurora events. About 150 pulsating auroral events over the Fennoscandian Lapland have been successfully analyzed for their average patch size, total patch area, and number of patches as a function of event time, typically 1-2 hr. An automatic routine has been develo...

Io’s atmosphere is predominately SO2 that is sustained by a combination of volcanic outgassing and sublimation. The loss from the atmosphere is the main mass source for Jupiter’s large magnetosphere. Numerous previous studies attributed various transient phenomena in Io’s environment and Jupiter’s magnetosphere to a sudden change in the mass loss f...

Io’s plasma interaction creates an electromagnetic coupling between Io and Jupiter through Alfvén waves triggering the generation of auroral footprints in Jupiter’s southern and northern hemispheres. The brightness of Io’s footprints undergoes periodic variations that are primarily modulated by Io’s local plasma interaction through the Poynting flu...

Energetic Particle Precipitation (EPP) has the potential to change the neutral atmospheric temperature at the mesopause region. Recent results, however, are inconsistent leaving the mechanism and the actual effect still unresolved. Here we have searched for electron precipitation events and investigated a possible correlation between D region elect...

Electric fields are a ubiquitous feature of the ionosphere and are intimately linked with aurora through particle precipitation and field-aligned currents. They exhibit order-of-magnitude changes on temporal and spatial scales of seconds and kilometres respectively which are not easy to measure; knowing their true magnitude and temporal variability...

The lower-thermosphere–ionosphere (LTI) system consists of the upper atmosphere and the lower part of the ionosphere, and as such comprises a complex system coupled to both the atmosphere below and space above. The atmospheric part of the LTI is dominated by laws of continuum fluid dynamics and chemistry, while the ionosphere is a plasma system con...

Io's atmosphere is predominately SO2 sustained by a combination of volcanic outgassing and sublimation. The loss from the atmosphere is the main mass source for Jupiter's large magnetosphere. Previous studies attributed various transient phenomena in Io's environment and Jupiter's magnetosphere to a sudden change in the mass loss from the atmospher...

A central challenge in the modeling of the near-collisionless expansion of a plasma thruster plume into vacuum is the inadequacy of traditional fluid closure relations for the electron species, such as isothermal or adiabatic laws, because the electron response in the plume is essentially kinetic and global. This work presents the validation of the...

Abstract. Electric fields are a ubiquitous feature of the ionosphere and are intimately linked with aurora through particle precipitation and field-aligned currents. We present a unique method to estimate ionospheric electric fields beside a dynamic auroral feature by solving the continuity equation for the metastable O⁺(²P) i...

Several recent studies derived the existence of plumes on Jupiter’s moon Europa. The only technique that provided multiple detections is the far-ultraviolet imaging observations of Europa in transit of Jupiter taken by the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope ( HST ). In this study, we reanalyze the three HST /S...

Global three-dimensional data are a key to understanding gravity waves in the mesosphere and lower thermosphere. MATS (Mesospheric Airglow/Aerosol Tomography and Spectroscopy) is a new Swedish satellite mission that addresses this need. It applies space-borne limb imaging in combination with tomographic and spectroscopic analysis to obtain gravity...

PRIME (Plasma Measurement with Micro Experiment) is a student experiment, launched on REXUS26 sounding rocket on 19th March 2019 as part of the REXUS/BEXUS programme. The project aimed to develop a miniature recoverable Free-Falling Unit for plasma parameter measurements in the lower ionosphere. Two identical Free-Falling Units can be ejected from...

We report both decreasing and increasing trends in the patch sizes during pulsating aurora events. About 150 pulsating auroral events over the Fennoscandian Lapland have been successfully analyzed for their average patch size, total patch area, and number of patches as a function of event time, typically 1–2 hr. An automatic routine has been develo...

Global three-dimensional data are a key to understanding gravity wave interactions in the mesosphere and lower thermosphere. MATS (Mesospheric Airglow/Aerosol Tomography and Spectroscopy) is a new Swedish satellite mission that addresses this need. It applies space-borne limb imaging in combination with tomographic and spectroscopic analysis to obt...

Characterising the photoelectron current induced by the Sun's UV radiation is crucial to ensure accurate daylight measurements from particle detectors. This article lays out the methodology used to address this problem in the case of the meteoric smoke particle detectors (MSPDs), developed by the Leibniz Institute of Atmospheric Physics in Kühlungs...

Characterizing the photoelectron current induced by the Sun’s UV radiation is crucial to ensure accurate daylight measurements from particle detectors. This article lays out the methodology used to address this problem in the case of the Meteor Smoke Particle Detectors (MSPDs), developed by the Leibniz Institute of Atmospheric Physics in Kühlungsbo...

Digital fluxgate magnetometers employ processing of the measured pickup signal to produce the value of the compensation current. Using pulse-width modulation with filtering for digital to analog conversion is a convenient approach, but it can introduce an intrinsic source of nonlinearity, which we discuss in this design note. A code shift of one le...

We present measurements of the electron density, the effective electron temperature, the plasma potential, and the electron energy probability function (EEPF) in the plume of a 1.5 kW-class SPT-100 Hall thruster, derived from cylindrical Langmuir probe measurements. The measurements were taken on the plume axis at distances between 550 and 1550 mm...

The Moon is an archetypal atmosphere-less celestial body in the Solar System. For such bodies, the environments are characterized by complex interaction among the space plasma, tenuous neutral gas, dust and the outermost layer of the surface. Here we propose the SELMA mission (Surface, Environment, and Lunar Magnetic Anomalies) to study how airless...

Photo-electrons and secondary electrons from particle precipitation enhance the incoherent scatter plasma line to levels sufficient for detection. When detectable the plasma line gives accurate measure of the electron density and can potentially be used to constrain incoherent scatter estimates of electron temperature. We investigate the statistica...

Far-ultraviolet observations of Ganymede's atmospheric emissions were obtained with the Space Telescope Imaging Spectrograph (STIS) onboard of the Hubble Space Telescope (HST) on several occasions between 1998 and 2014. We analyze the Lyman-α emission from four HST campaigns in order to constrain the abundance and variation of atomic hydrogen in Ga...

This paper describes the reconstruction of postflight trajectories of suborbital free flying units by using logged GPS raw data. We took the reconstruction as a global least squares optimization problem, using both the pseudo-range and Doppler observables, and solved it by using the trust-region-reflective algorithm, which enabled navigational solu...

The SPIDER sounding rocket, flown in February 2016, released ten Free Flying Units (FFUs) in the ionospheric E region (100 to 120 km) in order to investigate the plasma properties inside an auroral electrojet. In this region , the electric fields result in a relative drift motion of electrons and ions, and the induced unstability may create electro...

In December 2001, the Space Telescope Imaging Spectrograph of the Hubble Space Telescope obtained far-ultraviolet spectral images of Jupiter's moon Callisto. The leading and trailing hemispheres were observed in the spectral range 1190 Å to 1720 Å when the moon was at eastern and western elongations, respectively. We analyzed the hydrogen Lyman α (...

Atmospheric density profiles in the stratosphere and mesosphere are determined by means of low cost Global Positioning System (GPS) receivers on in situ rigid falling spheres released from a sounding rocket. Values below an altitude of 80 km are obtained. Aerodynamic drag relates atmospheric densities to other variables such as velocities of sphere...

High-resolution multispectral optical and incoherent scatter radar data are used to study the variability of pulsating aurora. Two events have been analysed, and the data combined with electron transport and ion chemistry modelling provide estimates of the energy and energy flux during both the ON and OFF periods of the pulsations. Both the energy...

Non-thermal echoes in incoherent scatter radar observations are occasionally seen in the high-latitude ionosphere. Such anomalous echoes are a manifestation of plasma instabilities on spatial scales matching the radar wavelength. Here we investigate the occurrence of a class of spatially localized anomalous echoes with an enhanced zero Doppler freq...

Bistable tape springs are suitable as deployable structures thanks to their high packaging ratio, self-deployment ability, low cost, light weight, and stiffness. A deployable booms assembly composed of four 1-m long bistable glass fiber tape springs was designed for the electromagnetically clean 3U CubeSat Small Explorer for Advanced Missions (SEAM...

We report far-ultraviolet observations of Europa in transit of Jupiter obtained with the Space Telescope Imaging Spectrograph of the Hubble Space Telescope on six occasions between 2014 December and 2015 March. Absorption of Jupiter's bright hydrogen Lyα dayglow is detected in a region several moon radii above the limb in all observations. The obse...

Technological advances leading to improved sensitivity of optical detectors have revealed that aurora contains a richness of dynamic and thin filamentary structures, but the source of the structured emissions is not fully understood. In addition, high-resolution radar data have indicated that thin auroral arcs can be correlated with highly varying...

The goal of this report is to outline the methods of DC-VLF magnetic interference control that we used during development, production and tests of a 3U CubeSat satellite.

We report far-ultraviolet observations of Ceres obtained with the Cosmic Origin Spectrograph (COS) of the Hubble Space Telescope in the search for atomic emissions from an exosphere. The derived brightnesses at the oxygen lines at 1304 Å and 1356 Å are consistent with zero signals within the 1-σ propagated statistical uncertainties. The OI 1304 Å b...

We analyze a large set of far-ultraviolet oxygen aurora images of Europa's atmosphere taken by Hubble's Space Telescope Imaging Spectrograph (HST/STIS) in 1999 and on 19 occasions between 2012 and 2015. We find that both brightness and aurora morphology undergo systematic variations correlated to the periodically changing plasma environment. The ti...

Auroral microphysics still remains partly unexplored. Cutting-edge ground-based optical observations using scientific complementary metal-oxide semiconductor (sCMOS) cameras recently enabled us to observe the fine-scale morphology of bright aurora at magnetic zenith for a variety of rapidly varying features for long uninterrupted periods. We report...

We presented an approach to understanding the performance of a fully digital fluxgate magnetometer. All elements of the design are important for the performance of the instrument, and the presence of the digital feed-back loop introduces certain peculiarities affecting the noise and dynamic performance of the instrument. Ultimately, the quantisatio...

Measurements of naturally enhanced ion acoustic line (NEIAL) echoes obtained with a five-antenna interferometric imaging radar system are presented. The observations were conducted with the European Incoherent SCATter (EISCAT) radar on Svalbard and the EISCAT Aperture Synthesis Imaging receivers (EASI) installed at the radar site. Four baselines of...

High resolution multi-monochromatic measurements of auroral emissions have revealed the first optical evidence of co-existing small-scale auroral features resulting from separate high and low energy populations of precipitating electrons on the same field line. The features exhibit completely separate motion and morphology. From emission ratios and...

The ratio of the emission line doublets from O+ at 732.0 nm (I 732) and 733.0 nm (I 733) has been measured in auroral conditions of low-energy electron precipitation from Svalbard (7820 north, 1583 east). Accurate determination of R = I 732/I 733 provides a powerful method for separating the density of the O+ levels in modeling of the emissions fro...

We present a statistical study of anomalous radar echoes observed in the auroral ionosphere thought to be signatures of Langmuir turbulence (LT). Data obtained with the EISCAT Svalbard radar during the international polar year (IPY) were searched for these anomalous echoes in the auroral F region. In incoherent scatter radar experiments LT may in c...

ISAAC-Infrared Spectroscopy to Analyse the middle Atmosphere Composition-was a student experiment launched from SSC's Esrange Space Centre, Swe-den, on 29th May 2014, on board the sounding rocket REXUS 15 in the frame of the REXUS/BEXUS programme. The main focus of the experiment was to implement an ejection system for two large Free Falling Units...

The EISCAT Svalbard Radar has two parabolic dishes. In order to attempt to implement radar aperture synthesis imaging methods three smaller, passive receive array antennas were built. Several science goals for this new receiver system exist, the primary of which is to study so called naturally enhanced ion acoustic lines. In order to compare radar...

Natural enhancements in the backscattered power of incoherent scatter radars up to 5 orders of magnitudes above the thermal backscatter are sometimes observed at high latitudes. Recently observations of enhancements in the backscattered power including a feature at zero Doppler shift have been reported. These enhancements are limited in altitude to...

Enhancements were observed in backscattered radar power during an ionospheric heating experiment from two distinct altitude regions in the auroral E region above Tromso. For the experiment the EISCAT Tromso heater was operated with O mode and X mode alternated at 4.04 MHz, close to the 3rd electron gyroharmonic. Ion-line data recorded with the EISC...

The main scientific objective of the MUSCAT Experiment is to develop a technique to reconstruct temperatures and density profiles in the middle atmosphere using active spherical probes. The MUSCAT experiment was launched on May 9, 2013 on the REXUS-13 sounding rocket from Esrange, in northern Sweden. The experiment ejected four probes that collecte...

A technique for collecting aerosol particles between altitudes of 85 and 17 km is described. Collection probes are ejected from a sounding rocket allowing for multi-point measurements. Each probe is equipped with 110 collection samples that are 3 mm in diameter. The collection samples are one of three types: standard transmission electron microscop...

Several experiments have been carried out or are in design phase under the lead of KTH using ejectable recoverable units to achieve variable scientific and technical objectives. This paper introduces the experiments with their goals, design solutions, results and lessons learned where appropriate. The RAIN (Rocket deployed Atmospheric probes conduc...

The RAIN (Rocket deployed Atmospheric probes conducting Independent measurements in Northern Sweden) experiment demonstrates a technique for collecting aerosol particles in the middle atmosphere using multiple probes ejected from a sounding rocket. Collection samples on each probe are exposed over varying height ranges between 80 and 22 km giving a...

A technique for collecting aerosol particles between altitudes of 85 and 17 km is described. Collection probes are ejected from a sounding rocket allowing for multi-point measurements. Each probe is equipped with 110 collection samples that are 3 mm in diameter. The collection samples are one of three types: standard transmission electron microscop...

1] The energy distribution of the electron precipitation responsible for extremely narrow (70 m) and dynamic auroral filaments is found to be sharply peaked at around 8 keV. The events were captured with high resolution low-light optical imagers located near Tromsø, Norway. The method uses imaging in two emissions which have different energy depen-...

The EISCAT incoherent radar on Svalbard has two dishes. In addition to this two dishes three smaller passive array antennas were built to attempt to implement radar aperture synthesis imaging. Limited to measurements of coherent backscatter the primary science goal of this new receiver system is to study so called naturally enhanced ion acoustic li...

The ratio of the emission line doublets from O+ at 732.0 nm (I732) and 733.0 nm (I733) has been measured in auroral conditions of low energy electron precipitation from Svalbard (78.20° north, 15.83° east) during two winters between 2003 and 2006. The value obtained for R = I732/I733 for the 2003-2004 season is 1.38 ± 0.02. This result is slightly...

A method of modelling small scale aurora in the magnetic zenith using radar and optical observations has been developed and is used to examine the background ionospheric electric field during the afterglow of an auroral event. Optical observations were obtained using the Auroral Structure and Kinetics (ASK) instrument whilst radar observations were...

Observations of the development of small-scale structures in aurorae are not uncommon. However, their appearance and cause are not well understood. One suggestion is that arc splitting is caused by inertial Alfven waves. In this presentation a novel method to use multi-monochromatic optical observations to estimate the characteristics of the precip...

Investigation of the wave particle interaction in the magnetosphere and ionosphere by controllable experiment in near Earth space is in focus of modern space geophysics. We propose to stimulate auroral precipitation by changing parameters of the Flow Cyclotron Maser (FCM) and test the FCM model itself. One of the main goals of the project is induci...

Two discrete auroral arc filaments, with widths of less than 1 km, have been analysed using multi-station, multi-monochromatic optical observations from small and medium field-of-view imagers and the EISCAT radar. The energy and flux of the precipitating electrons, volume emission rates and local electric fields in the ionosphere have been determin...

The objective of the SQUID project is to develop and in flight verify a miniature version of a wire boom deployment mechanism to be used for electric field measurements in the ionosphere. In February 2011 a small ejectable payload, built by a team of students from The Royal Institute of Technology (KTH), was launched from Esrange on-board the REXUS...

On 16 December 2001, a variable and structured aurora associated with a period of high solar wind velocity and low solar wind density was recorded through optical, radar, and particle measurements from the ground and space. A comprehensive analysis of this data set is carried out using a coupled auroral electron deposition and ion chemistry model....

High-resolution, multi-spectral data from the ground-based low-light auroral imager ASK (Auroral Structure and Kinetics) are used to characterize the fine structure of black aurora. Sixteen events comprising sheared and unsheared black arcs, as well as black patches and rings, constitute the analysed dataset. Simultaneous measurements of emissions...

The principal tendency in space research nowadays is the decrease of spacecrafts dimensions, weight and costs. The recent challenges are cubesats, more and more used especially in scientific space research. The most complicated problem for the realization of scientific experiments onboard cubesats remains the development of small and light but enou...

Here we present electron temperature variations observed with incoherent scatter radar during a European Incoherent Scatter Scientific Association Heating experiment with high-frequency (HF) radio wave transmission at frequencies above the peak ionospheric critical frequency. The electron temperature increased from 2000 K up to 2800 K during the HF...

We present an analysis of flickering (2–10 Hz) auroras observed with a state-of-the-art multispectral imaging system, Auroral Structure and Kinetics, located in Tromsø, Norway. Short (1–2 s) periods of flickering aurora have been identified in which the frequency of the brightness oscillations decreases or increases smoothly over time. To the autho...

Auroral arcs can develop small-scale distortions known as vortex streets or curls. Other common and somewhat larger spatially periodic distortions are auroral folds. In this event study we present simultaneous wide and narrow field imager observations of a third kind of structuring, on even smaller spatial scales. Boundary undulations, or “ruffs”,...

The fluxgate magnetometers (FGM) are probably the most widespread instruments used onboard spacecrafts for both scientific and service purposes. The recent trend to decrease the weight and size of the spacecrafts requires creating as small as possible but enough sensitive FGM. A joint Swedish-Ukrainian team made the development of such a magnetomet...