Three-scale structure of diffusion region in the presence of cold ions

2016 ◽  
Vol 121 (12) ◽  
pp. 12,001-12,013 ◽  
Author(s):  
A. Divin ◽  
Yu. V. Khotyaintsev ◽  
A. Vaivads ◽  
M. André ◽  
S. Toledo-Redondo ◽  
...  
Keyword(s):  
Scale Structure ◽  
Diffusion Region ◽  
Cold Ions

Ionospheric ions in the magnetosphere: Important at large and small scales

2020 ◽  
Author(s):  
Mats André ◽  
Sergio Toledo-Redondo ◽  
Andrew W Yau
Keyword(s):  
Electric Field ◽  
Magnetic Reconnection ◽  
Energy Transport ◽  
Small Scale ◽  
Diffusion Region ◽  
Positive Ions ◽  
Small Scales ◽  
Outflow Rate ◽  
Long Time ◽  
Cold Ions

<p><span lang="EN-US">Cold (eV) ions of ionospheric origin dominate the number density of most of the volume of the magnetosphere during most of the time. </span><span lang="EN-US">Supersonic flows of cold positive ions are common and can cause a negatively charged wake behind a positively charged spacecraft. The associated induced electric field can be observed and can be used to study the cold ions. We present observations from the Cluster and MMS spacecraft showing how a charged satellite, and also individual charged wire booms of  an electric field instrument, can be used to investigate cold ion populations. </span><span lang="EN-US">Ionospheric ions affect large scales, including the Alfvén velocity and </span><span lang="EN-US"> </span><span lang="EN-US">thus energy transport with waves and the magnetic reconnection rate. These ions also affect small-scale kinetic plasma physics, including the Hall physics and wave instabilities associated with magnetic reconnection. Concerning large scales, we summarize observations from several spacecraft and show that a typical total outflow rate of ionospheric ions is 10<sup>26</sup> ions/s and that many of these ions stay cold also after a long time in the magnetosphere.  Concerning small scales, we show examples of how cold ions modify the Hall physics of thin current sheets, including magnetic reconnection separatrices. On small kinetic scales the cold ions introduce a new length-scale, a gyro radius between the gyro radii of hot (keV) ions and electrons. </span><span lang="EN-US">The Hall currents carried by electrons can be partially cancelled by the cold ions when electrons and the magnetized cold ions ExB drift together. Also, close to a reconnection X-line an additional diffusion region can be formed (regions associated with hot and cold ions, and with electrons, total of three).</span></p>

scholarly journals Ion-scale structure in Mercury's magnetopause reconnection diffusion region

2016 ◽  
Vol 43 (12) ◽  
pp. 5935-5942 ◽  
Author(s):  
Daniel J. Gershman ◽  
John C. Dorelli ◽  
Gina A. DiBraccio ◽  
Jim M. Raines ◽  
James A. Slavin ◽  
...  
Keyword(s):  
Scale Structure ◽  
Diffusion Region ◽  
Magnetopause Reconnection

scholarly journals Quantification of Cold-Ion Beams in a Magnetic Reconnection Jet

2021 ◽  
Vol 8 ◽  
Author(s):  
Yu-Xuan Li ◽  
Wen-Ya Li ◽  
Bin-Bin Tang ◽  
C. Norgren ◽  
Jian-Sen He ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Plasma Sheet ◽  
Ion Beams ◽  
Distribution Functions ◽  
Diffusion Region ◽  
Hot Plasma ◽  
Order Of Magnitude ◽  
Velocity Distribution Functions ◽  
Cold Ions ◽  
Field Lines

Cold (few eV) ions of ionospheric origin are widely observed in the lobe region of Earth’s magnetotail and can enter the ion jet region after magnetic reconnection is triggered in the magnetotail. Here, we investigate a magnetotail crossing with cold ions in one tailward and two earthward ion jets observed by the Magnetospheric Multiscale (MMS) constellation of spacecraft. Cold ions co-existing with hot plasma-sheet ions form types of ion velocity distribution functions (VDFs) in the three jets. In one earthward jet, MMS observe cold-ion beams with large velocities parallel to the magnetic fields, and we perform quantitative analysis on the ion VDFs in this jet. The cold ions, together with the hot ions, are reconnection outflow ions and are a minor population in terms of number density inside this jet. The average bulk speed of the cold-ion beams is approximately 38% larger than that of the hot plasma-sheet ions. The cold-ion beams inside the explored jet are about one order of magnitude colder than the hot plasma-sheet ions. These cold-ion beams could be accelerated by the Hall electric field in the cold ion diffusion region and the shrinking magnetic field lines through the Fermi effect.

Multi-scale structure of the electron diffusion region

2007 ◽  
Vol 34 (13) ◽  
pp. n/a-n/a ◽  
Author(s):  
H. Karimabadi ◽  
W. Daughton ◽  
J. Scudder
Keyword(s):  
Scale Structure ◽  
Diffusion Region ◽  
Electron Diffusion ◽  
Multi Scale

Zeitstrukturen im Jazz

2014 ◽  
Vol 59 (1) ◽  
pp. 79-92
Author(s):  
Alexander Becker
Keyword(s):  
Large Scale ◽  
Large Scale Structure ◽  
Time Frame ◽  
Scale Structure ◽  
Classical Form ◽  
Jazz Music ◽  
The Moment

Wie erlebt der Hörer Jazz? Bei dieser Frage geht es unter anderem um die Art und Weise, wie Jazz die Zeit des Hörens gestaltet. Ein an klassischer Musik geschultes Ohr erwartet von musikalischer Zeitgestaltung, den zeitlichen Rahmen, der durch Anfang und Ende gesetzt ist, von innen heraus zu strukturieren und neu zu konstituieren. Doch das ist keine Erwartung, die dem Jazz gerecht wird. Im Jazz wird der Moment nicht im Hinblick auf ein Ziel gestaltet, das von einer übergeordneten Struktur bereitgestellt wird, sondern so, dass er den Bewegungsimpuls zum nächsten Moment weiterträgt. Wie wirkt sich dieses Prinzip der Zeitgestaltung auf die musikalische Form im Großen aus? Der Aufsatz untersucht diese Frage anhand von Beispielen, an denen sich der Weg der Transformation von einer klassischen zu einer dem Jazz angemessenen Form gut nachverfolgen lässt.<br><br>How do listeners experience Jazz? This is a question also about how Jazz music organizes the listening time. A classically educated listener expects a piece of music to structure, unify and thereby re-constitute the externally given time frame. Such an expectation is foreign to Jazz music which doesn’t relate the moment to a goal provided by a large scale structure. Rather, one moment is carried on to the next, preserving the stimulus potentially ad infinitum. How does such an organization of time affect the large scale form? The paper tries to answer this question by analyzing two examples which permit to trace the transformation of a classical form into a form germane to Jazz music.

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