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id stringlengths 40 40	title stringlengths 15 120	text stringlengths 41 3.14k	source stringclasses 2 values
e8c1296a5de0de5754b971d7f978a1c5a4fe4996	where δ {\displaystyle \delta } is the current	where δ {\displaystyle \delta } is the current sheet half-thickness. this relation uses that the magnetic field reverses over a distance of ∼ 2 δ {\displaystyle \sim 2\delta }. by matching the ideal electric field outside of the layer with the resistive electric field e = 1 σ j {\displaystyle \mathbf {e} ={\frac {1}{\s...	wikipedia
58d092b82345aee7d0ddf9f3761b551effeb2bfa	where e y {\displaystyle e_{y}} is the out-of-plane	where e y {\displaystyle e_{y}} is the out-of-plane electric field, v in {\displaystyle v_{\text{in}}} is the characteristic inflow velocity, and b in {\displaystyle b_{\text{in}}} is the characteristic upstream magnetic field strength. by neglecting displacement current, the low-frequency ampere's law, j = 1 μ 0 ∇ × b...	wikipedia
df72904fb22b5cb421bdc837475451cb0e247679	the sweet–parker model describes time-independent magnetic reconnection in	the sweet–parker model describes time-independent magnetic reconnection in the resistive mhd framework when the reconnecting magnetic fields are antiparallel (oppositely directed) and effects related to viscosity and compressibility are unimportant. the initial velocity is simply an e × b {\displaystyle e\times b} velo...	wikipedia
8420da5d309eb695a36dd2f8374f0fbec8c6b86e	the first theoretical framework of magnetic reconnection was	the first theoretical framework of magnetic reconnection was established by peter sweet and eugene parker at a conference in 1956. sweet pointed out that by pushing two plasmas with oppositely directed magnetic fields together, resistive diffusion is able to occur on a length scale much shorter than a typical equilibri...	wikipedia
53342c1168deabd8408efdae8077e298453bd48a	in three dimensions, the geometry of the field	in three dimensions, the geometry of the field lines become more complicated than the two-dimensional case and it is possible for reconnection to occur in regions where a separator does not exist, but with the field lines connected by steep gradients. these regions are known as quasi-separatrix layers (qsls), and have ...	wikipedia
d4b5abb75d6d7ab06984f8ea782c217744a1ee56	in two dimensions, the most common type of	in two dimensions, the most common type of magnetic reconnection is separator reconnection, in which four separate magnetic domains exchange magnetic field lines. domains in a magnetic plasma are separated by separatrix surfaces: curved surfaces in space that divide different bundles of flux. field lines on one side of...	wikipedia
5311dfce8d717f7080225ccea8046277fc2f6677	in an electrically conductive plasma, magnetic field lines	in an electrically conductive plasma, magnetic field lines are grouped into 'domains'— bundles of field lines that connect from a particular place to another particular place, and that are topologically distinct from other field lines nearby. this topology is approximately preserved even when the magnetic field itself ...	wikipedia
8c2643aaf7b95747e71a7f1e6debf63ca4a32cf0	the qualitative description of the reconnection process is	the qualitative description of the reconnection process is such that magnetic field lines from different magnetic domains (defined by the field line connectivity) are spliced to one another, changing their patterns of connectivity with respect to the sources. it is a violation of an approximate conservation law in plas...	wikipedia
ac53f3f6044ae8bcc28bcbab66c96ece0f31e016	a current problem in plasma physics is that	a current problem in plasma physics is that observed reconnection happens much faster than predicted by mhd in high lundquist number plasmas (i.e. fast magnetic reconnection). solar flares, for example, proceed 13–14 orders of magnitude faster than a naive calculation would suggest, and several orders of magnitude fast...	wikipedia
d71f5b24e5fafcbf57465fe0f4e3e24aea4d684e	dungey coined the term "reconnection" because he initially	dungey coined the term "reconnection" because he initially envisaged field lines of the inflow topology breaking and then joining together again in the outflow topology. however, this means that magnetic monopoles would exist, albeit for a very limited period, which would violate maxwell's equation that the divergence ...	wikipedia
c24c790bd74afac1e4eb3c1d52f5b72563baf9cc	the resistivity of the current layer allows magnetic	the resistivity of the current layer allows magnetic flux from either side to diffuse through the current layer, cancelling outflux from the other side of the boundary. however, the small spatial scale of the current sheet makes the magnetic reynolds number small and so this alone can make the diffusion term dominate i...	wikipedia
a15748fd2ac89ae7174656c2ebdbe6f56701ddeb	in a plasma (ionized gas), for all but	in a plasma (ionized gas), for all but exceptionally high frequency phenomena, the second term on the right-hand side of this equation, the displacement current, is negligible compared to the effect of the free current j {\displaystyle \mathbf {j} } and this equation reduces to ampére's law for free charges. the displa...	wikipedia
db9a7d7276ccb9cd0ff87e840e0fc7ded4faf292	∇ × b = μ j + μ	∇ × b = μ j + μ ϵ ∂ e ∂ t. {\displaystyle \nabla \times \mathbf {b} =\mu \mathbf {j} +\mu \epsilon {\frac {\partial \mathbf {e} }{\partial t}}.}	wikipedia
14a74e6b35eb4fd4dfea848c339efc7fa259d473	magnetic reconnection is a breakdown of "ideal-magnetohydrodynamics" and	magnetic reconnection is a breakdown of "ideal-magnetohydrodynamics" and so of " alfvén's theorem " (also called the "frozen-in flux theorem") which applies to large-scale regions of a highly-conducting magnetoplasma, for which the magnetic reynolds number is very large: this makes the convective term in the induction ...	wikipedia
ec5fd1e44a5e282f982370278cf21d3e3a1490c0	in the meantime, the first theoretical framework of	in the meantime, the first theoretical framework of magnetic reconnection was established by peter sweet and eugene parker at a conference in 1956. sweet pointed out that by pushing two plasmas with oppositely directed magnetic fields together, resistive diffusion is able to occur on a length scale much shorter than a ...	wikipedia
7c9d956a8117e9ce9828ede452806c3bac9b2394	james dungey is credited with first use of	james dungey is credited with first use of the term “magnetic reconnection” in his 1950 phd thesis, to explain the coupling of mass, energy and momentum from the solar wind into earth's magnetosphere. the concept was published for the first time in a seminal paper in 1961. dungey coined the term "reconnection" because ...	wikipedia
babd73b8cf935aa0e33f75b3f69737217369a347	ron giovanelli is credited with the first publication	ron giovanelli is credited with the first publication invoking magnetic energy release as a potential mechanism for particle acceleration in solar flares. giovanelli proposed in 1946 that solar flares stem from the energy obtained by charged particles influenced by induced electric fields within close proximity of suns...	wikipedia
e7f87f7cf9eecc653d1f008754ebd7494dd27fa2	the concept of magnetic reconnection was developed in	the concept of magnetic reconnection was developed in parallel by researchers working in solar physics and in the interaction between the solar wind and magnetized planets. this reflects the bidirectional nature of reconnection, which can either disconnect formerly connected magnetic fields or connect formerly disconne...	wikipedia
662257a7270e4981571839f23b03ee5e8373b94a	magnetic reconnection is a physical process occurring in	magnetic reconnection is a physical process occurring in electrically conducting plasmas, in which the magnetic topology is rearranged and magnetic energy is converted to kinetic energy, thermal energy, and particle acceleration. magnetic reconnection involves plasma flows at a substantial fraction of the alfvén wave s...	wikipedia
f1a3b124566be5b22c11628187a1f78ef7b0819c	an oscillation in the conductivity of a material	an oscillation in the conductivity of a material that occurs at low temperatures in the presence of very intense magnetic fields, the shubnikov–de haas effect (sdh) is a macroscopic manifestation of the inherent quantum mechanical nature of matter. it is often used to determine the effective mass of charge carriers, al...	wikipedia
bb82a92536af27293c81abcee8056e168e77f332	the effect is related to the de haas–van	the effect is related to the de haas–van alphen effect, which is the name given to the corresponding oscillations in magnetization. the signature of each effect is a periodic waveform when plotted as a function of inverse magnetic field. the " frequency " of the magnetoresistance oscillations indicate areas of extremal...	wikipedia
935b4f7aad2914c4fdc5bb761165dc03ada0617e	for a given sample, all factors including the	for a given sample, all factors including the electron density n on the right hand side of relationship (3) are constant. when plotting the index i of an edge channel versus the reciprocal of its magnetic flux density 1/ b, one obtains a straight line with slope 2 e /(nh). since the electron charge e is known and also ...	wikipedia
71e3000f1a4733d802f2615610365fd54a39fc6c	shubnikov–de haas oscillations can be used to determine	shubnikov–de haas oscillations can be used to determine the two-dimensional electron density of a sample. for a given magnetic flux Φ {\displaystyle \phi } the maximum number d of electrons with spin s = 1/2 per landau level is	wikipedia
50a3a7119f593a212e29cccf18463204f63cddb7	the result of zero resistivity between the contacts	the result of zero resistivity between the contacts 2 and 3 is a consequence of the electrons being mobile only in the edge channels of the sample. the situation would be different if a landau level came close to the fermi energy e. any electrons in that level would become mobile as their energy approaches the fermi en...	wikipedia
f31ea1adde674badc51707cef60e9620594a9f95	in other words, the chemical potentials μ and	in other words, the chemical potentials μ and μ and their respective voltages μ / e and μ / e are the same. as a consequence of no drop of voltage between the contacts 2 and 3, the current i experiences zero resistivity r in between contacts 2 and 3	wikipedia
4c5359294369f727d922ea44fb1aa645396ced25	fig 2 shows a sample with four contacts.	fig 2 shows a sample with four contacts. to drive a current through the sample, a voltage is applied between the contacts 1 and 4. a voltage is measured between the contacts 2 and 3. suppose electrons leave the 1st contact, then are transmitted from contact 1 to contact 2, then from contact 2 to contact 3, then from co...	wikipedia
442c13b627439b8c5842b2ae59c9fba1b104b470	where e denotes the electron charge, h denotes	where e denotes the electron charge, h denotes the planck constant, and i stands for the number of edge channels. the matrix t denotes the probability of transmission of a negatively charged particle (i.e. of an electron) from a contact l ≠ m to another contact m. the net current i in relationship (1) is made up of the...	wikipedia
9e0b30630079f716d1da0972563f0752a3bb523e	the landauer–büttiker approach is used to describe transport	the landauer–büttiker approach is used to describe transport of electrons in this particular sample. the landauer–büttiker approach allows calculation of net currents i flowing between a number of contacts 1 ≤ m ≤ n. in its simplified form, the net current i of contact m with chemical potential μ reads	wikipedia
23cf5f6f7fb6c751ae9391f4de0cdf1f4bc4de65	fig 1 shows the fermi energy e located	fig 1 shows the fermi energy e located in between two landau levels. electrons become mobile as their energy levels cross the fermi energy e. with the fermi energy e in between two landau levels, scattering of electrons will occur only at the edges of a sample where the levels are bent. the corresponding electron state...	wikipedia
0391f56623ab4bc0ecada1d7985d95e7716ebe97	consider a two-dimensional quantum gas of electrons confined	consider a two-dimensional quantum gas of electrons confined in a sample with given width and with edges. in the presence of a magnetic flux density b, the energy eigenvalues of this system are described by landau levels. as shown in fig 1, these levels are equidistant along the vertical axis. each energy level is subs...	wikipedia
1949befde61031f1bd2d96b0127742c1f5e2638d	at sufficiently low temperatures and high magnetic fields,	at sufficiently low temperatures and high magnetic fields, the free electrons in the conduction band of a metal, semimetal, or narrow band gap semiconductor will behave like simple harmonic oscillators. when the magnetic field strength is changed, the oscillation period of the simple harmonic oscillators changes propor...	wikipedia
d04d49e3c3508789610e2ba9bcd0886007d514d2	an oscillation in the conductivity of a material	an oscillation in the conductivity of a material that occurs at low temperatures in the presence of very intense magnetic fields, the shubnikov–de haas effect (sdh) is a macroscopic manifestation of the inherent quantum mechanical nature of matter. it is often used to determine the effective mass of charge carriers (el...	wikipedia
b3e1da6666a3537fc5a1d77be09652167c825d82	bashar ahmad nuseibeh is a computing engineer who	bashar ahmad nuseibeh is a computing engineer who currently holds a number of roles. he is professor of computing at the open university, a professor of software engineering at the university of limerick, and chief scientist of the irish software research centre lero. he is also an honorary professor at university coll...	wikipedia
dd6c93bc3be8fb81be8cc4737ce1e05ad9993e0a	he was a visiting professor at imperial college,	he was a visiting professor at imperial college, and is currently a visiting professor at both university college london (ucl) and the national institute of informatics (nii), japan. he is also a professor at the university of limerick.	wikipedia
075a87c0975b9570c7520166642ad19ddd4520e6	in 2001, nuseibeh moved to the open university	in 2001, nuseibeh moved to the open university as professor of computing, where he was director of research from 2002 to 2008. from 2009 to 2012, he took a secondment to lero, the irish software research centre, as professor of software engineering and chief scientist. in recent years, nuseibeh has become a leading exp...	wikipedia
468ce8fb8cb05e5ee34de7e1af160770b8957a1e	nuseibeh studied at the university of sussex where	nuseibeh studied at the university of sussex where he received a bsc in computer systems engineering in 1988. he then moved to imperial college london to complete his msc, which he was awarded in 1989. he remained at imperial college london for the next decade, firstly to complete his phd in software engineering in 199...	wikipedia
64312db53b82e8aefcfad73171d8b4c2d589bd2b	bashar ahmad nuseibeh (born 1967) is a computing	bashar ahmad nuseibeh (born 1967) is a computing engineer who currently holds a number of roles. he is professor of computing at the open university, a professor of software engineering at the university of limerick, and chief scientist of the irish software research centre lero.	wikipedia
8a0232b2cfbe78a71d1dda7489a03b6e1acce032	kohei okuno joined j1 league club gamba osaka	kohei okuno joined j1 league club gamba osaka in 2019 and was handed the number 26 jersey. prior to that he spent 2 seasons on loan with gamba osaka under-23 while he completed his high school education. he played 4 games in 2017 and 2 more substitute appearances in 2018.	wikipedia
173ec77af6b5b019e28155594e8071bca2ee1941	kohei okuno (奥野耕平, okuno kōhei, born april	kohei okuno (奥野耕平, okuno kōhei, born april 3, 2000) is a japanese footballer who plays as a defensive midfielder for j1 league club shonan bellmare.	wikipedia
f1920665b7e6ca79c994093f166871e29e3098e9	carla maria penz is a butterfly comparative morphologist	carla maria penz is a butterfly comparative morphologist and systematist, and the former doris zemurray stone chair in biodiversity at the university of new orleans. her research also focuses on natural history and behavior, mostly of neotropical butterflies. she is currently professor emeritus at the university of new...	wikipedia