scholarly journals Suprathermal electron acceleration during reconnection onset in the magnetotail

2011 ◽  
Vol 29 (10) ◽  
pp. 1917-1925 ◽  
Author(s):  
A. Vaivads ◽  
A. Retinò ◽  
Yu. V. Khotyaintsev ◽  
M. André
Keyword(s):  
Magnetic Flux ◽  
Electric Field ◽  
Plasma Sheet ◽  
Electron Acceleration ◽  
Flux Transport ◽  
Energetic Electrons ◽  
Flux Tubes ◽  
Suprathermal Electron ◽  
Suprathermal Electrons ◽  
Pile Up

Abstract. We study one event of reconnection onset associated to a small substorm on 27 September 2006 by using Cluster observations at inter-spacecraft separation of about 10 000 km. We focus on the acceleration of suprathermal electrons during different stages of reconnection. We show that several distinct stages of acceleration occur: (1) moderate acceleration during reconnection of pre-existing plasma sheet flux tubes, (2) stronger acceleration during reconnection of lobe flux tubes, (3) production of the most energetic electrons within dipolarization fronts (magnetic pile-up regions). The strongest acceleration is reached at the location of Bz maxima inside the magnetic pile-up region where the reconnection jet stops. Very strong localized dawn-dusk electric field are observed within the magnetic pile-up regions and are associated to most of the magnetic flux transport.

scholarly journals Large-scale fluctuations of PSBL magnetic flux tubes induced by the field-aligned motion of highly accelerated ions

2010 ◽  
Vol 28 (6) ◽  
pp. 1273-1288 ◽  
Author(s):  
E. E. Grigorenko ◽  
T. M. Burinskaya ◽  
M. Shevelev ◽  
J.-A. Sauvaud ◽  
L. M. Zelenyi
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Plasma Sheet ◽  
Large Scale ◽  
Low Frequency ◽  
Main Magnetic Field ◽  
Sudden Increase ◽  
Data Set ◽  
Flux Tubes ◽  
Magnetic Flux Tubes

Abstract. We present a comprehensive analysis of magnetic field and plasma data measured in the course of 170 crossings of the lobeward edge of Plasma Sheet Boundary Layer (PSBL) in the Earth's magnetotail by Cluster spacecraft. We found that large-scale fluctuations of the magnetic flux tubes have been registered during intervals of propagation of high velocity field-aligned ions. The observed kink-like oscillations propagate earthward along the main magnetic field with phase velocities of the order of local Alfvén velocity and have typical wavelengths ~5–20 RE, and frequencies of the order of 0.004–0.02 Hz. The oscillations of PSBL magnetic flux tubes are manifested also in a sudden increase of drift velocity of cold lobe ions streaming tailward. Since in the majority of PSBL crossings in our data set, the densities of currents corresponding to electron-ion relative drift have been low, the investigation of Kelvin-Helmholtz (K-H) instability in a bounded flow sandwiched between the plasma sheet and the lobe has been performed to analyze its relevance to generation of the observed ultra-low frequency oscillations with wavelengths much larger than the flow width. The calculations have shown that, when plasma conditions are favorable for the excitation of K-H instability at least at one of the flow boundaries, kink-like ultra-low frequency waves, resembling the experimentally observed ones, could become unstable and efficiently develop in the system.

scholarly journals Average characteristics of the midtail plasma sheet in different dynamic regimes of the magnetosphere

2004 ◽  
Vol 22 (6) ◽  
pp. 2107-2113 ◽  
Author(s):  
N. P. Dmitrieva ◽  
V. A. Sergeev ◽  
M. A. Shukhtina
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Growth Phase ◽  
Plasma Sheet ◽  
Transfer Rate ◽  
Flux Transport ◽  
Data Set ◽  
Magnetospheric Convection ◽  
Flux Transfer ◽  
Night Flux

Abstract. We study average characteristics of plasma sheet convection in the middle tail during different magnetospheric states (Steady Magnetospheric Convection, SMC, and substorms) using simultaneous magnetotail (Geotail, 15-35 RE downtail) and solar wind (Wind spacecraft) observations during 3.5 years. (1) A large data set allowed us to obtain the average values of the plasma sheet magnetic flux transfer rate (Ey and directly compare it with the dayside transfer rate (Emod for different magnetospheric states. The results confirm the magnetic flux imbalance model suggested by Russell and McPherron (1973), namely: during SMC periods the day-to-night flux transport rate equals the global Earthward plasma sheet convection; during the substorm growth phase the plasma sheet convection is suppressed on the average by 40%, whereas during the substorm expansion phase it twice exceeds the day-to-night global flux transfer rate. (2) Different types of substorms were revealed. About 1/3 of all substorms considered displayed very weak growth in the tail lobe magnetic field before the onset. For these events the plasma sheet transport was found to be in a balance with the day-to-night flux transfer, as in the SMC events. However, the lobe magnetic field value in these cases was as large as that in the substorms with a classic growth phase just before the onset (both values exceed the average level of the lobe field during the SMC). Also, in both groups similar configurational changes (magnetic field stretching and plasma sheet thinning) were observed before the substorm onset. (3) Superimposed epoch analysis showed that the plasma sheet during the late substorm recovery phase has the characteristics similar to those found during SMC events, the SMC could be a natural magnetospheric state following the substorm.

scholarly journals DNA bioelectric field: a futuristic bioelectric marker of cancer, aging and death – A working hypothesis

2021 ◽  
Vol 3 (1) ◽  
pp. 68-79
Author(s):  
Matti Pitkänen ◽  
◽  
Reza Rastmanesh ◽  
Keyword(s):  
Magnetic Flux ◽  
Electric Field ◽  
Longitudinal Electric Field ◽  
Magnetic Flux Tube ◽  
Flux Tubes ◽  
Dna Strands ◽  
Standard Picture ◽  
Magnetic Flux Tubes ◽  
Sticky Ends ◽  
The Difference

Telomeres are associated with the ends of DNA double strands. The lengths of the telomeres are controlled by the telomerase enzyme. The shortening of the telomeres is known to relate to aging. In cancers, telomere lengths are abnormally short. Telomeres could act as buffers shielding the part of DNA coding for the proteins. For cancer cells, germ cells and stem cells the length of the telomeres is not varying. There is an analogy with microtubules, which are highly dynamical and carry a longitudinal electric field, whose strength correlates with the microtubule length. Could sticky ends generate a longitudinal field along DNA double strand with strength determined by the lengths of the sticky ends? In the standard picture the flux of the longitudinal electric field would be proportional to the difference of the negative charges associated with the sticky ends. In TGD framework, DNA strands are accompanied by the dark analog of DNA with codons realized as 3-proton units at magnetic flux tubes parallel to DNA strands and neutralizing the negative charge of ordinary DNA except at the sticky ends. This allows considering the possibility that opposite sticky ends carry opposite charges generating a longitudinal electric field along the magnetic flux tube associated with the system. DNA/Telomere bioelectric field could serve as a novel bioelectric marker to be used for prognostic and diagnostic purposes in researches of cancer, aging, surgery grafts and rejuvenation. We propsed that DNA bioelectric field can be used as a futuristic bioelectric marker of cancer, aging and death.

The magnetic flux transport along the -Esw direction in the magnetotails on Mars and Venus

2020 ◽  
Author(s):  
Lihui Chai ◽  
James Slavin ◽  
Yong Wei ◽  
Weixing Wan ◽  
Charlie F. Bowers ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Flux ◽  
Pressure Gradient ◽  
Plasma Sheet ◽  
Magnetic Pressure ◽  
Mass Loading ◽  
Flux Transport ◽  
Loading Effect

<p>The induced magnetotails on Mars and Venus are considered to arise through the interplanetary magnetic field (IMF) draping around the planet and the solar wind deceleration due to the mass loading effect. They have very similar structures as that on Earth, two magnetic lobes of opposite radial magnetic fields and a plasma sheet in between. However, the orientation and geometry of the induced magnetotails are controlled by the IMF, not the planetary intrinsic magnetic field. In this study, we present another characteristic of the induced magnetotails on Mars and Venus with the observations of MAVEN and Venus Express. It is found that the magnetic flux in the induced magnetotails on Mars and Venus are inhomogeneous. There is more magnetic flux in the +E hemisphere than -E hemisphere. The magnetic flux is observed to transport gradually from the +E hemisphere to the -E hemisphere along the magnetotail. The magnetotail magnetic flux transport seems to be faster on Mars than that at Venus. Based on these observations, we suggest that the finite gyro-radius effect of the planetary ions that are picked up by the solar wind is responsible to the magnetic flux inhomogeneity and transport in the induced magnetotails. The role of the magnetic pressure gradient in the magnetotail will be discussed.</p>

scholarly journals The storm time central plasma sheet

2002 ◽  
Vol 20 (11) ◽  
pp. 1737-1741 ◽  
Author(s):  
R. Schödel ◽  
K. Dierschke ◽  
W. Baumjohann ◽  
R. Nakamura ◽  
T. Mukai
Keyword(s):  
Magnetic Flux ◽  
Plasma Sheet ◽  
Neutral Line ◽  
Magnetic Storms ◽  
Main Phase ◽  
Plasma Convection ◽  
Flux Transport ◽  
Storm Main Phase ◽  
Central Plasma ◽  
Central Plasma Sheet

Abstract. The plasma sheet plays a key role during magnetic storms because it is the bottleneck through which large amounts of magnetic flux that have been eroded from the dayside magnetopause have to be returned to the dayside magnetosphere. Using about five years of Geotail data we studied the average properties of the near- and midtail central plasma sheet (CPS) in the 10–30 RE range during magnetic storms. The earthward flux transport rate is greatly enhanced during the storm main phase, but shows a significant earthward decrease. Hence, since the magnetic flux cannot be circulated at a sufficient rate, this leads to an average dipolarization of the central plasma sheet. An increase of the specific entropy of the CPS ion population by a factor of about two during the storm main phase provides evidence for nonadiabatic heating processes. The direction of flux transport during the main phase is consistent with the possible formation of a near-Earth neutral line beyond ~20 RE.Key words. Magnetospheric physics (plasma convection; plasma sheet; storms and substorms)

scholarly journals Oscillatory magnetic flux tube slippage in the plasma sheet

2006 ◽  
Vol 24 (6) ◽  
pp. 1695-1704 ◽  
Author(s):  
A. A. Petrukovich ◽  
T. l. Zhang ◽  
W. Baumjohann ◽  
R. Nakamura ◽  
A. Runov ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Plasma Sheet ◽  
Large Scale ◽  
Magnetic Flux Tube ◽  
Dynamical Structure ◽  
Magnetic Field Direction ◽  
Flux Tubes ◽  
Stationary Structure ◽  
Magnetic Flux Tubes ◽  
The Magnetic Field

Abstract. Cluster observations in the magnetotail revealed an abundance of strongly inclined current sheets. We determine the magnetic configuration of a particular subset of such phenomena: a series of sheet crossings, having significantly differing inclinations and occurring during quiet conditions. These wave-like variations appear to propagate azimuthally and their magnetic amplitude and magnetic gradient (current density) inside the sheet are proportional to their steepness (degree of inlcination). In spite of significant normal direction changes between neighboring crossings up to 150°, the magnetic field direction inside the neutral sheet remains almost constant. The wavelengths and spatial amplitudes are of the order of 2–5 RE. These observations are interpreted as crossings of a quasi-periodic dynamical structure produced by almost vertical slippage motion of the neighboring magnetic flux tubes in the high-β plasma sheet, rather than large-scale flapping of a stationary structure.

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