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Publications (4 of 4) Show all publications
Li, W., Andre, M., Khotyaintsev, Y. V., Vaivads, A., Graham, D. B., Toledo-Redondo, S., . . . Strangeway, R. J. (2016). Kinetic evidence of magnetic reconnection due to Kelvin-Helmholtz waves. Geophysical Research Letters, 43(11), 5635-5643
Open this publication in new window or tab >>Kinetic evidence of magnetic reconnection due to Kelvin-Helmholtz waves
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2016 (English)In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 43, no 11, p. 5635-5643Article in journal (Refereed) Published
Abstract [en]

The Kelvin-Helmholtz (KH) instability at the Earth's magnetopause is predominantly excited during northward interplanetary magnetic field (IMF). Magnetic reconnection due to KH waves has been suggested as one of the mechanisms to transfer solar wind plasma into the magnetosphere. We investigate KH waves observed at the magnetopause by the Magnetospheric Multiscale (MMS) mission; in particular, we study the trailing edges of KH waves with Alfvenic ion jets. We observe gradual mixing of magnetospheric and magnetosheath ions at the boundary layer. The magnetospheric electrons with energy up to 80keV are observed on the magnetosheath side of the jets, which indicates that they escape into the magnetosheath through reconnected magnetic field lines. At the same time, the low-energy (below 100eV) magnetosheath electrons enter the magnetosphere and are heated in the field-aligned direction at the high-density edge of the jets. Our observations provide unambiguous kinetic evidence for ongoing reconnection due to KH waves.

Place, publisher, year, edition, pages
Blackwell Publishing, 2016
Keywords
kinetic evidence, reconnection, Kelvin-Helmholtz wave
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:kth:diva-253541 (URN)10.1002/2016GL069192 (DOI)000379851800012 ()2-s2.0-84977100261 (Scopus ID)
Funder
Swedish National Space Board, 164/14, 176/15
Note

QC 20190625

Available from: 2019-06-15 Created: 2019-06-15 Last updated: 2019-06-25Bibliographically approved
Norgren, C., André, M., Graham, D. B. B., Khotyaintsev, Y. V. V. & Vaivads, A. (2015). Slow electron holes in multicomponent plasmas. Geophysical Research Letters, 42(18), 7264-7272
Open this publication in new window or tab >>Slow electron holes in multicomponent plasmas
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2015 (English)In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 42, no 18, p. 7264-7272Article in journal (Refereed) Published
Abstract [en]

Electrostatic solitary waves (ESWs), often interpreted as electron phase space holes, are commonly observed in plasmas and are manifestations of strongly nonlinear processes. Often slow ESWs are observed, suggesting generation by the Buneman instability. The instability criteria, however, are generally not satisfied. We show how slow electron holes can be generated by a modified Buneman instability in a plasma that includes a slow electron beam on top of a warm thermal electron background. This lowers the required current for marginal instability and allows for generation of slow electron holes for a wide range of beam parameters that covers expected plasma distributions in space, for example, in magnetic reconnection regions. At higher beam speeds, the electron-electron beam instability becomes dominant instead, producing faster electron holes. The range of phase speeds for this model is consistent with a statistical set of observations at the magnetopause made by Cluster.

Keywords
Multi-component plasma, Modified Buneman instability, Ion-electron instability, Slow electron holes
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:kth:diva-253558 (URN)10.1002/2015GL065390 (DOI)000363412400004 ()2-s2.0-84945218399 (Scopus ID)
Funder
Swedish Research Council, 23/12:2
Note

QC 20190617

Available from: 2019-06-15 Created: 2019-06-15 Last updated: 2019-06-17Bibliographically approved
Norgren, C., André, M., Vaivads, A. & Khotyaintsev, Y. V. (2015). Slow electron phase space holes: Magnetotail observations. Geophysical Research Letters, 42(6), 1654-1661
Open this publication in new window or tab >>Slow electron phase space holes: Magnetotail observations
2015 (English)In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 42, no 6, p. 1654-1661Article in journal (Refereed) Published
Abstract [en]

We report multispacecraft observations of slow electrostatic solitary waves in the plasma sheet boundary layer. The electrostatic solitary waves are embedded in a region with field-aligned electron flows and are interpreted as electron phase space holes. We make unambiguous velocity and length estimates of the electron holes, v(EH)approximate to 500 km/s and l(||)approximate to 2-4(De), where l(||) is the parallel half width. We do not detect any magnetic signature of the holes. The electrostatic potentials of the holes are of the order e/k(B)T(e)approximate to 10%, indicating that they can affect electron motion and further couple the electron and ion dynamics.

Keywords
slow electron holes, multispacecraft
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-253559 (URN)10.1002/2015GL063218 (DOI)000353170000006 ()2-s2.0-84927747899 (Scopus ID)
Note

QC 20190617

Available from: 2019-06-15 Created: 2019-06-15 Last updated: 2019-06-17Bibliographically approved
Norgren, C., Vaivads, A., Khotyaintsev, Y. V. & André, M. (2012). Lower Hybrid Drift Waves: Space Observations. Physical Review Letters, 109(5), Article ID 055001.
Open this publication in new window or tab >>Lower Hybrid Drift Waves: Space Observations
2012 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 109, no 5, article id 055001Article in journal (Refereed) Published
Abstract [en]

Lower hybrid drift waves (LHDWs) are commonly observed at plasma boundaries in space and laboratory, often having the strongest measured electric fields within these regions. We use data from two of the Cluster satellites (C3 and C4) located in Earth's magnetotail and separated by a distance of the order of the electron gyroscale. These conditions allow us, for the first time, to make cross-spacecraft correlations of the LHDWs and to determine the phase velocity and wavelength of the LHDWs. Our results are in good agreement with the theoretical prediction. We show that the electrostatic potential of LHDWs is linearly related to fluctuations in the magnetic field magnitude, which allows us to determine the velocity vector through the relation integral delta Edt . v = phi(delta B parallel to). The electrostatic potential fluctuations correspond to similar to 10% of the electron temperature, which suggests that the waves can strongly affect the electron dynamics.

National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-253610 (URN)10.1103/PhysRevLett.109.055001 (DOI)000306994900014 ()2-s2.0-84864425350 (Scopus ID)
Note

QC 20190619

Available from: 2019-06-15 Created: 2019-06-15 Last updated: 2019-06-19Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-6561-2337

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