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De Spiegeleer, AlexandreORCID iD iconorcid.org/0000-0003-1167-8055
Publications (10 of 11) Show all publications
De Spiegeleer, A., Hamrin, M., Gunell, H., Volwerk, M., Andersson, L., Karlsson, T., . . . Kistler, L. M. (2019). Oscillatory Flows in the Magnetotail Plasma Sheet: Cluster Observations of the Distribution Function. Journal of Geophysical Research - Space Physics, 124(4), 2736-2754
Open this publication in new window or tab >>Oscillatory Flows in the Magnetotail Plasma Sheet: Cluster Observations of the Distribution Function
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2019 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 124, no 4, p. 2736-2754Article in journal (Refereed) Published
Abstract [en]

Plasma dynamics in Earth's magnetotail is often studied using moments of the distribution function, which results in losing information on the kinetic properties of the plasma. To better understand oscillatory flows observed in the midtail plasma sheet, we investigate two events, one in each hemisphere, in the transition region between the central plasma sheet and the lobes using the 2-D ion distribution function from the Cluster 4 spacecraft. In this case study, the oscillatory flows are a manifestation of repeated ion flux enhancements with pitch angle changing from 0 degrees to 180 degrees in the Northern Hemisphere and from 180 degrees to 0 degrees in the Southern Hemisphere. Similar pitch angle signatures are observed seven times in about 80 min for the Southern Hemisphere event and three times in about 80 min for the Northern Hemisphere event. The ion flux enhancements observed for both events are slightly shifted in time between different energy channels, indicating a possible time-of-flight effect from which we estimate that the source of particle is located similar to 5-25R(E) and similar to 40-107R(E) tailward of the spacecraft for the Southern and Northern Hemisphere event, respectively. Using a test particle simulation, we obtain similar to 21-46 R-E for the Southern Hemisphere event and tailward of X similar to - 65R(E) (outside the validity region of the model) for the Northern Hemisphere event. We discuss possible sources that could cause the enhancements of ion flux.

Place, publisher, year, edition, pages
AMER GEOPHYSICAL UNION, 2019
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:umu:diva-162349 (URN)10.1029/2018JA026116 (DOI)000477707800027 ()
Available from: 2019-08-27 Created: 2019-08-27 Last updated: 2019-08-27Bibliographically approved
Vaverka, J., Nakamura, T., Kero, J., Mann, I., De Spiegeleer, A., Hamrin, M., . . . Pellinen-Wannberg, A. (2018). Comparison of Dust Impact and Solitary Wave Signatures Detected by Multiple Electric Field Antennas Onboard the MMS Spacecraft. Journal of Geophysical Research - Space Physics, 123(8), 6119-6129
Open this publication in new window or tab >>Comparison of Dust Impact and Solitary Wave Signatures Detected by Multiple Electric Field Antennas Onboard the MMS Spacecraft
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2018 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 123, no 8, p. 6119-6129Article in journal (Refereed) Published
Abstract [en]

Dust impact detection by electric field instruments is a relatively new method. However, the influence of dust impacts on electric field measurements is not completely understood and explained. A better understanding is very important for reliable dust impact identification, especially in environments with low dust impact rate. Using data from Earth-orbiting Magnetospheric Multiscale mission (MMS) spacecraft, we present a study of various pulses detected simultaneously by multiple electric field antennas in the monopole (probe-to-spacecraft potential measurement) and dipole (probe-to-probe potential measurement) configurations. The study includes data obtained during an impact of a millimeter-sized object. We show that the identification of dust impacts by a single antenna is a very challenging issue in environments where solitary waves are commonly present and that some pulses can be easily misinterpreted as dust impacts. We used data from multiple antennas to distinguish between changes in the spacecraft potential (dust impact) and structures in the ambient plasma or electric field. Our results indicate that an impact cloud is in some cases able to influence the potential of the electric field antenna during its expansion.

Place, publisher, year, edition, pages
American Geophysical Union (AGU), 2018
Keywords
dust, solitary waves, electric field instruments, MMS, dust impacts
National Category
Fusion, Plasma and Space Physics Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:umu:diva-152903 (URN)10.1029/2018JA025380 (DOI)000445731300002 ()
Funder
Swedish National Space Board, 110/14
Available from: 2018-10-30 Created: 2018-10-30 Last updated: 2018-10-30Bibliographically approved
Pitkänen, T., Kullen, A., Shi, Q. Q., Hamrin, M., De Spiegeleer, A. & Nishimura, Y. (2018). Convection electric field and plasma convection in a twisted magnetotail: t THEMIS case study 1-2 January 2009. Journal of Geophysical Research - Space Physics, 123(9), 7486-7497
Open this publication in new window or tab >>Convection electric field and plasma convection in a twisted magnetotail: t THEMIS case study 1-2 January 2009
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2018 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 123, no 9, p. 7486-7497Article in journal (Refereed) Published
Abstract [en]

We investigate THEMIS satellite measurements made in a tail-aligned constellation during a time interval on 1-2 January 2009, which has previously been attributed to an interval of an interplanetary magnetic fieldB(y)-driven magnetotail twisting. We find evidence for that the orientation of the convection electric field in the tail is twist-mode dependent. For earthward flow and a negative twist (induced tail B-y < 0), the electric field is found to have northward E-z and tailward E-x components. During a positive twist (induced tail B-y > 0), the directions of E-z and E-x are reversed. The E-y component shows the expected dawn-to-dusk direction for earthward flow. The electric field components preserve their orientation across the neutral sheet, and a quasi-collinear field is observed irrespective to the tail distance. The electric field associated with the tailward flow has an opposite direction compared to the earthward flow for the negative twist. For the positive twist, the results are less clear. The corresponding plasma convection and thus the magnetic flux transport have an opposite dawn-dusk direction above and below the neutral sheet. The directions depend on the tail twist mode. The hemispherically asymmetric earthward plasma flows are suggested to be a manifestation of an asymmetric Dungey cycle in a twisted magnetotail. The role of tailward flows deserve further investigation.

Place, publisher, year, edition, pages
American Geophysical Union (AGU), 2018
National Category
Fusion, Plasma and Space Physics Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:umu:diva-153821 (URN)10.1029/2018JA025688 (DOI)000448376600025 ()
Available from: 2018-12-11 Created: 2018-12-11 Last updated: 2018-12-11Bibliographically approved
Vaverka, J., Pellinen-Wannberg, A., Kero, J., Mann, I., De Spiegeleer, A., Hamrin, M., . . . Pitkänen, T. (2017). Detection of EMPs generated by meteoroid impacts on the MMS spacecraft and problems with signal interpretation. In: 2017 XXXIInd General Assembly and Scientific Symposium of the International Union of Radio Science (URSI GASS): . Paper presented at 32nd General Assembly and Scientific Symposium of the International-Union-of-Radio-Science (URSI GASS), Montreal, QC, Canada, 19-26 August, 2017. IEEE
Open this publication in new window or tab >>Detection of EMPs generated by meteoroid impacts on the MMS spacecraft and problems with signal interpretation
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2017 (English)In: 2017 XXXIInd General Assembly and Scientific Symposium of the International Union of Radio Science (URSI GASS), IEEE, 2017Conference paper, Published paper (Refereed)
Abstract [en]

Signatures of hypervelocity dust impacts detected by electric field instruments are still not completely understood. We have used the electric field instrument onboard one of the MMS spacecraft orbiting the Earth since 2015 to study various pulses in the measured electric field detected simultaneously by multiple antennas. This unique instrument allows a detailed investigation of registered waveforms. The preliminary results shown that the solitary waves can generate similar pulses as dust impacts and detected pulses can easily by misinterpreted when only one antenna is used.

Place, publisher, year, edition, pages
IEEE, 2017
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:umu:diva-163055 (URN)10.23919/URSIGASS.2017.8105218 (DOI)000463723600268 ()978-90-825987-0-4 (ISBN)
Conference
32nd General Assembly and Scientific Symposium of the International-Union-of-Radio-Science (URSI GASS), Montreal, QC, Canada, 19-26 August, 2017
Available from: 2019-09-09 Created: 2019-09-09 Last updated: 2019-09-09Bibliographically approved
Vaverka, J., Pellinen-Wannberg, A., Kero, J., Mann, I., De Spiegeleer, A., Hamrin, M., . . . Pitkänen, T. (2017). Detection of meteoroid hypervelocity impacts on the Cluster spacecraft: First results. Journal of Geophysical Research - Space Physics, 122(6), 6485-6494
Open this publication in new window or tab >>Detection of meteoroid hypervelocity impacts on the Cluster spacecraft: First results
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2017 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 122, no 6, p. 6485-6494Article in journal (Refereed) Published
Abstract [en]

We present the first study of dust impact events on one of the Earth-orbiting Cluster satellites. The events were identified in the measurements of the wide band data (WBD) instrument on board the satellite operating in monopole configuration. Since 2009 the instrument is operating in this configuration due to the loss of three electric probes and is therefore measuring the potential between the only operating antenna and the spacecraft body. Our study shows that the WBD instrument on Cluster 1 is able to detect pulses generated by dust impacts and discusses four such events. The presence of instrumental effects, intensive natural waves, noncontinuous sampling modes, and the automatic gain control complicates this detection. Due to all these features, we conclude that the Cluster spacecraft are not ideal for dust impact studies. We show that the duration and amplitudes of the pulses recorded by Cluster are similar to pulses detected by STEREO, and the shape of the pulses can be described with the model of the recollection of impact cloud electrons by the positively charged spacecraft. We estimate that the detected impacts were generated by micron-sized grains with velocities in the order of tens of km/s.

Keywords
hypervelocity impact, dust detection, interplanetary dust
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:umu:diva-138045 (URN)10.1002/2016JA023755 (DOI)000405534800040 ()
Available from: 2017-08-14 Created: 2017-08-14 Last updated: 2019-09-09Bibliographically approved
De Spiegeleer, A., Hamrin, M., Pitkänen, T., Volwerk, M., Mann, I., Nilsson, H., . . . Vaverka, J. (2017). Low-frequency oscillatory flow signatures and high-speed flows in the Earth's magnetotail. Journal of Geophysical Research - Space Physics, 122(7), 7042-7056
Open this publication in new window or tab >>Low-frequency oscillatory flow signatures and high-speed flows in the Earth's magnetotail
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2017 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 122, no 7, p. 7042-7056Article in journal (Refereed) Published
Abstract [en]

Using plasma sheet data from Cluster 1 spacecraft from 2001 till 2011, we statistically investigate oscillatory signatures in the plasma bulk flow. These periodic oscillations are compared to high-speed and quiet flows. Periodic oscillations are observed approximately 8% of the time, while high-speed flows and quiet flows are observed around 0.5% and 12% of the time, respectively. We remark that periodic oscillations can roughly occur everywhere for x(gsm) < -10 R-E and |y(gsm)| < 10 RE, while quiet flows mainly occur toward the flanks of this region and toward x = -10 R-E. The relation between the geomagnetic and solar activity and the occurrence of periodic oscillations is investigated and reveal that periodic oscillations occur for most Kp values and solar activity, while quiet flows are more common during low magnetospheric and solar activity. We find that the median oscillation frequency of periodic oscillations is 1.7 mHz and the median duration of the oscillation events is 41 min. We also observe that their associated Poynting vectors show a tendency to be earthward (S-x >= 0). Finally, the distribution of high-speed flows and periodic oscillations as a function of the velocity is investigated and reveals that thresholds lower than 200 km/s should not be used to identify high-speed flows as it could result in misinterpreting a periodic oscillations for a high-speed flow.

Place, publisher, year, edition, pages
Washington: American Geophysical Union (AGU), 2017
Keywords
bursty bulk flows, plasma sheet, cluster observations, magnetic field, neutral sheet, magnetosphere, dependence, midtail
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:umu:diva-139015 (URN)10.1002/2017JA024076 (DOI)000407627100008 ()
Funder
Swedish National Space Board, 271/14
Available from: 2017-09-14 Created: 2017-09-14 Last updated: 2019-09-09Bibliographically approved
Yao, S., Wang, X. G., Shi, Q. Q., Pitkänen, T., Hamrin, M., Yao, Z. H., . . . Liu, J. (2017). Observations of kinetic-size magnetic holes in the magnetosheath. Journal of Geophysical Research - Space Physics, 122(2), 1990-2000
Open this publication in new window or tab >>Observations of kinetic-size magnetic holes in the magnetosheath
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2017 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 122, no 2, p. 1990-2000Article in journal (Refereed) Published
Abstract [en]

Magnetic holes (MHs), with a scale much greater than ρ(proton gyroradius), have been widely reported in various regions of space plasmas. On the other hand, kinetic-size magnetic holes (KSMHs), previously called small-size magnetic holes, with a scale of the order of magnitude of or less than ρi have only been reported in the Earth's magnetospheric plasma sheet. In this study, we report such KSMHs in the magnetosheath whereby we use measurements from the Magnetospheric Multiscale mission, which provides three-dimensional (3-D) particle distribution measurements with a resolution much higher than previous missions. The MHs have been observed in a scale of 10-20 ρe (electron gyroradii) and lasted 0.1-0.3 s. Distinctive electron dynamics features are observed, while no substantial deviations in ion data are seen. It is found that at the 90 degrees pitch angle, the flux of electrons with energy 34-66 eV decreased, while for electrons of energy 109-1024 eV increased inside the MHs. We also find the electron flow vortex perpendicular to the magnetic field, a feature self-consistent with the magnetic depression. Moreover, the calculated current density is mainly contributed by the electron diamagnetic drift, and the electron vortex flow is the diamagnetic drift flow. The electron magnetohydrodynamics soliton is considered as a possible generation mechanism for the KSMHs with the scale size of 10-20 ρe.

Place, publisher, year, edition, pages
AMER GEOPHYSICAL UNION, 2017
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:umu:diva-133552 (URN)10.1002/2016JA023858 (DOI)000397022900038 ()
Note

Special Section: Magnetospheric Multiscale (MMS) mission results throughout the first primary mission phase

Available from: 2017-04-12 Created: 2017-04-12 Last updated: 2019-09-09Bibliographically approved
Vaverka, J., Pellinen-Wannberg, A., Kero, J., Mann, I., De Spiegeleer, A., Hamrin, M., . . . Pitkänen, T. (2017). Potential of Earth Orbiting Spacecraft Influenced by Meteoroid Hypervelocity Impacts. IEEE Transactions on Plasma Science, 45(8), 2048-2055
Open this publication in new window or tab >>Potential of Earth Orbiting Spacecraft Influenced by Meteoroid Hypervelocity Impacts
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2017 (English)In: IEEE Transactions on Plasma Science, ISSN 0093-3813, E-ISSN 1939-9375, Vol. 45, no 8, p. 2048-2055Article in journal (Refereed) Published
Abstract [en]

Detection of hypervelocity impacts on a spacecraft body using electric field instruments has been established as a new method for monitoring of dust grains in our solar system. Voyager, WIND, Cassini, and STEREO spacecraft have shown that this technique can be a complementary method to conventional dust detectors. This approach uses fast short time changes in the spacecraft potential generated by hypervelocity dust impacts, which can be detected by monopole electric field instruments as a pulse in the measured electric field. The shape and the duration of the pulse strongly depend on parameters of the ambient plasma environment. This fact is very important for Earth orbiting spacecraft crossing various regions of the Earth's magnetosphere where the concentration and the temperature of plasma particles change significantly. We present the numerical simulations of spacecraft charging focused on changes in the spacecraft potential generated by dust impacts in various locations of the Earth's magnetosphere. We show that identical dust impacts generate significantly larger pulses in regions with lower electron density. We discuss the influence of the photoelectron distribution for dust impact detections showing that a small amount of energetic photoelectrons significantly increases the potential of the spacecraft body and the pulse duration. We also show that the active spacecraft potential control (ASPOC) instrument onboard the cluster spacecraft strongly reduces the amplitude and the duration of the pulse resulting in difficulties of dust detection when ASPOC is ON. Simulation of dust impacts is compared with pulses detected by the Earth orbiting cluster spacecraft in the last part of Section III.

Keywords
Dust grains, hypervelocity impacts, meteoroids, spacecraft charging
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:umu:diva-140978 (URN)10.1109/TPS.2017.2676984 (DOI)000407374400031 ()
Funder
Swedish National Space Board, 110/14Swedish National Space Board, 77/14
Available from: 2017-11-01 Created: 2017-11-01 Last updated: 2018-06-09Bibliographically approved
Yao, S. T., Shi, Q. Q., Li, Z. Y., Wang, X. G., Tian, A. M., Sun, W. J., . . . Reme, H. (2016). Propagation of small size magnetic holes in the magnetospheric plasma sheet. Journal of Geophysical Research - Space Physics, 121(6), 5510-5519
Open this publication in new window or tab >>Propagation of small size magnetic holes in the magnetospheric plasma sheet
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2016 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 121, no 6, p. 5510-5519Article in journal (Refereed) Published
Abstract [en]

Magnetic holes (MHs), characteristic structures where the magnetic field magnitude decreases significantly, have been frequently observed in space plasmas. Particularly, small size magnetic holes (SSMHs) which the scale is less than or close to the proton gyroradius are recently detected in the magnetospheric plasma sheet. In this study of Cluster observations, by the timing method, the minimum directional difference (MDD) method, and the spatiotemporal difference (STD) method, we obtain the propagation velocity of SSMHs in the plasma flow frame. Furthermore, based on electron magnetohydrodynamics (EMHD) theory we calculate the velocity, width, and depth of the electron solitary wave and compare it to SSMH observations. The result shows a good accord between the theory and the observation.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2016
Keywords
magnetic holes, plasma sheet, propagation velocity, electron magnetohydrodynamics, KdV soliton, small size
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:umu:diva-126763 (URN)10.1002/2016JA022741 (DOI)000383421100037 ()
Available from: 2016-10-18 Created: 2016-10-13 Last updated: 2018-06-09Bibliographically approved
Vaverka, J., Pellinen-Wannberg, A., Kero, J., Mann, I., De Spiegeleer, A., Hamrin, M., . . . Pitkänen, T. (2016). Spacecraft potential influenced by meteoroid hypervelocity impacts. In: : . Paper presented at 14th Spacecraft Charging Technology Conference, ESA/ESTEC, Noordwijk, NL, April 4-8, 2016. IEEE
Open this publication in new window or tab >>Spacecraft potential influenced by meteoroid hypervelocity impacts
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2016 (English)Conference paper, Published paper (Other academic)
Abstract [en]

Detection of hypervelocity impacts on a spacecraft body using electric field instruments has been established as a new method for monitoring of dust grains in our solar system. Voyager, WIND, Cassini, and STEREO spacecraft have shown that this technique can be a complementary method to conventional dust detectors. This approach uses fast short time changes in the spacecraft potential generated by hypervelocity dust impacts, which can be detected by monopole electric field instruments as a pulse in the measured electric field. The shape and the duration of the pulse strongly depend on parameters of the ambient plasma environment. This fact is very important for Earth orbiting spacecraft crossing various regions of the Earth's magnetosphere where the concentration and the temperature of plasma particles change significantly. We present the numerical simulations of spacecraft charging focused on changes in the spacecraft potential generated by dust impacts in various locations of the Earth's magnetosphere. We show that identical dust impacts generate significantly larger pulses in regions with lower electron density. We discuss the influence of the photoelectron distribution for dust impact detections showing that a small amount of energetic photoelectrons significantly increases the potential of the spacecraft body and the pulse duration. We also show that the active spacecraft potential control (ASPOC) instrument onboard the cluster spacecraft strongly reduces the amplitude and the duration of the pulse resulting in difficulties of dust detection when ASPOC is ON. Simulation of dust impacts is compared with pulses detected by the Earth orbiting cluster spacecraft in the last part of Section III.

Place, publisher, year, edition, pages
IEEE, 2016
Series
IEEE Transactions on Plasma Science, ISSN 0093-3813
National Category
Fusion, Plasma and Space Physics
Research subject
Space and Plasma Physics
Identifiers
urn:nbn:se:umu:diva-129378 (URN)10.1109/TPS.2017.2676984 (DOI)
Conference
14th Spacecraft Charging Technology Conference, ESA/ESTEC, Noordwijk, NL, April 4-8, 2016
Funder
Swedish National Space Board
Available from: 2016-12-22 Created: 2016-12-22 Last updated: 2019-09-09Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-1167-8055

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