The word "open field line" is sometimes used casually when the speaker means "a line that that reconnects somewhere outside our region of interest" or sloppily in saying "magnetic reconnection involves breaking and reattaching field lines" when the speaker means "... crossing and reattaching field lines."
Nonsense, ben. You are grossly misrepresenting the facts when you claim the terms are only sometimes used casually or that the speakers actually only mean "crossing" field lines. I've proven in thread after thread with citation after citation that the top mainstream scientists have used the terms "breaking", "open" and "reconnecting" to describe what happens to field lines. And they talk about them as if they are real entities and these are literal events. And these statements were in peer-reviewed papers and other scientific oriented publications ... hardly casual conversation. So again, you are misrepresenting the facts.
May I use you as an illustration of the importance of careful language in physics?
Perhaps you should use the following examples as illustrations of that :
http://www.springerlink.com/content/q64134u3u72q3664/ "Magnetic reconnection in the corona and the loop prominence phenomenon, R. A. Kopp and G. W. Pneuman ... snip ... 1976 ... snip ... the flare event then
tears open the field lines"
http://www.newscientist.com/article/mg13318114.500-.html "When the solar wind blows: The northern lights are a sign of the awesome power that the Earth receives from the solar wind. The big puzzle is how, 07 March 1992 ... snip ... This is because
reconnection also happens in the centre of the tail, converting pairs of open field lines back into closed field lines within the magnetosphere and releasing the stored energy."
http://www.springerlink.com/content/n817203820715m76/ "
Reconnection on open field lines ahead of coronal mass ejections ... snip ... 1995 ... Plasma and magnetic field signatures from 29 November 1990 indicate that the Ulysses spacecraft passed through a series of interplanetary structures that were most likely formed by magnetic
reconnection on open field lines ahead of a coronal mass ejection (CME)."
http://www.agu.org/revgeophys/mccoma01/node4.html "Tongues, bottles, and disconnected loops:
The opening and closing of the interplanetary magnetic field, David J. McComas, Space and Atmospheric Sciences Group, Los Alamos National Laboratory, Los Alamos, New Mexico ... snip ... 1995 ... snip ... 4.
Closing of Open Magnetic Field Lines ... snip ... As a consequence, the only reasonable method of reducing the IMF magnitude in interplanetary space seems to be via
reconnection between oppositely directed, previously open field lines [ McComas et al., 1989, 1991; McComas, 1994]."
http://www.agu.org/pubs/crossref/1996/95JA02857.shtml " JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 101, NO. A5, PAGES 10,805–10,816, 1996, MHD simulations of the
transition of magnetic reconnection from closed to open field lines"
http://books.google.com/books?id=nf...pUqyOYT&sig=I3ecdSkSIpadpdiTij4FyWFrzME&hl=en "Magnetic Reconnection: MHD Theory And Applications by Eric Ronald Priest and Terry Forbes ... snip ... published 2000 ... reconnection is essentially a topological restructuring of a magnetic field caused by a change in the connectivity of its field lines. ... snip ... 11.1 Large-Scale Eruptive Phenomena ...
The opening of the field lines in such an active region by a CME leads to the formation of flare ribbons and loops ... snip ... both ribbons and loops are formed by the process of magnetic energy release
as open field lines reconnect to become closed loops again. ... snip ... since the CME flux ropes are likely to
contain a mixture of both closed and open field lines".
http://www.taborcommunications.com/archives/100178.html "WEATHERING THE SUBSTORM by J. William Bell, NCSA Senior Science Writer, 05/25/01... snip ... This release marks the beginning of the expansion phase, in which the
open field lines reconnect to their appropriate pole on the earth."
http://books.google.com/books?id=ZV...=LucBLysBZH63Q2rhRrd05FdKjRo&hl=en#PPA1014,M1 "The Century of Space Science by J. A. M. Bleeker, Johannes Geiss, M. Huber ... snip ... 2001 ... snip ... it was Hoyle's student Dungey (1961) who first applied the reconnection concept to the interaction of the solar wind and the magnetosphere. His famous diagram (Figure 10) showed that, with a southward IMF,
magnetospheric field lines may merge with the IMF on the front side, become open, get pulled across the polar cap, and be transferred back into closed field lines at a reconnection site on the rear side."
http://www.irf.se/Publications/IRFreport280.pdf "Proceeding of the Magnetic Reconnection Meeting in Kiruna, Sweden,
September 2002 ... snip ... The distinguishing characteristics of MR are considered to be ... snip ... ,
and open magnetic field lines ... snip ... Since
one of the requirements for MR is open field lines, it should be distinguishable from processes that occur on closed field lines."
http://scitation.aip.org/getabs/ser...00009000005001925000001&idtype=cvips&gifs=yes "A new laboratory experiment on magnetic reconnection, Phys. Plasmas 9, 1925*(2002) ... snip ... R. L. Stenzel, J. M. Urrutia, M. Griskey, and K. Strohmaier, Department of Physics and Astronomy, University of California ... snip .... In a large laboratory plasma reconnection of three-dimensional (3-D) magnetic fields is studied in the parameter regime of electron magnetohydrodynamics (EMHD). ... snip ...
By definition, the change in field topology from closed to open field lines involves reconnection "
http://www.mist.ac.uk/mistg203.html "RAS/MIST discussion meeting, 10th October 2003 ... snip ... Identifying
the open-closed field line boundary in magnetospheric and ionospheric data sets"
Space Science*By L. K. Harra, Keith O. Mason ... snip ... 2004 ... snip ... The occurence of reconnection in the vicinity of the subsolar dayside magnetopause
creates two 'open' magnetic flux tubes, which have one end located in the north and south polar ionospheres, and the other ends out in the solar wind. Just after they have undergone reconnection, these field lines have a sharp kink as they thread through the dayside magnetopause. The magnetic tension of these field lines at the magnetopause acts to try to straighten them. ... snip ... a continual cycle of magnetospheric convection is set up,
with open field lines being created by dayside reconnection"
http://www.springerlink.com/content/g542121367532401/ " Magnetic Star-Disk Interaction in Classical T Tauri Stars ... snip ... 2004 ... snip ... "They found the magnetic field
to open up and reconnect periodically, launching a pulsed outflow"
http://books.google.com/books?id=xP...sig=YrBdGl8vsFpFYL_Cq0-QUEuc8n0&hl=en#PPP1,M1 "The Sun, Solar Analogs and the Climate*By Joanna D. Haigh, Michael Lockwood, Mark S. Giampapa, Advanced Course 34, 2004, Swiss Society for Astrophysics and Astronomy .. snip ... 2.6 The Role of Magnetic Reconnection in the Solar Corona and Inner Heliosphere ... snip ... Where
open field lines come into close proximity and have opposite polarity, reconnection can take place at an X-line ... snip ... Wang, et. al. (1996) show how
field lines must be opened at the leading edge of a coronal hole extension by reconnection of this type and then close again at its trailing edge"
http://www.journals.uchicago.edu/doi/abs/10.1086/425126 "The Origin of Postflare Loops, N. R. Sheeley, Jr., H. P. Warren, and Y.-M. Wang... snip ... 2004 ... snip ... we conclude that postflare loops are the end result of the formation, filling, deceleration, and cooling of magnetic loops produced by the
reconnection of field lines blown open in the flare."
http://209.85.173.104/search?q=cach...f+"open+field+lines"&hl=en&ct=clnk&cd=8&gl=us "
The importance of open field lines for the generation of daytime rayed aurora and plasma turbulence, E. M. Blixt, K. Oksavik, T. Grydeland, A. Stromme, Geophysical Research Abstracts, Vol. 7, 9-2-2005"
http://www.nersc.gov/news/science/reconnection.php "Understanding Magnetic Explosions, On December 6, 2006, Global Positioning System (GPS) devices suddenly started malfunctioning all over the Earth. The culprit: a solar flare. ... snip ... The basic idea is that the churning of ionized gas amplifies the magnetic fields in a plasma by twisting and folding them—kinetic energy being converted into magnetic energy.
When the magnetic field lines touch or cross, they break, reconnect, and reverse direction ... snip ... Constantly in motion, the field lines sometimes touch or cross and reverse direction in a process called magnetic reconnection.
Open field lines instead of loops show that plasma is being ejected outward as a solar flare."
http://209.85.173.104/search?q=cach...ld+lines+are+opened"&hl=en&ct=clnk&cd=9&gl=us "Ionospheric signatures of the low-latitude boundary layer under
conditions of northward IMF and small clock angle ... snip ... 2006 ... snip ... Under conditions of south-
ward IMF closed
field lines are opened by reconnection near the equatorial magnetopause."
http://209.85.173.104/search?q=cach...lines"+reconnection&hl=en&ct=clnk&cd=12&gl=us "CORONAL MAGNETIC FIELD TOPOLOGY OVER FILAMENT CHANNELS: IMPLICATION FOR CORONAL MASS EJECTION INITIATIONS, Yan Li and Janet Luhmann ... snip ... 2006 ... snip ... It seems difficult for the eruption process to
open the field lines and at the same time to release energy. The so-called breakout model (Antiochos 1998; Antiochos etal.1999)
solves this problem ... snip ... through magnetic reconnection between the large-scale overlying arcade and lower central arcade immediately over the sheared structure to let out the eruption."
http://solarphysics.livingreviews.org/Articles/lrsp-2008-1/ "Flare Observations by Arnold O.*Benz, Institute of Astronomy, ETH ... snip ... 3.1 Geometry of the coronal magnetic field ... snip ... This suggests that
in a third of all flares at least one of the four ends of reconnecting field lines is open. ... snip ...
The energy release by open and a closed field lines, termed interchange reconnection, has been proposed some time ago (Heyvaerts et al., 1977; Fisk et al., 1999) and applied more recently to in situ observations in a CME (Crooker and Webb, 2006)."
http://www.physics.soton.ac.uk/teach/year4/notes/phys6004/PHYS6004f8.doc "SPACE PLASMA PHYSICS – Consequences of reconnection: convection ... snip ...
the open field lines produced by magnetopause reconnection ... snip ...
where they can be opened again by reconnection and so start another cycle. We call this large scale circulation of magnetic flux (with its frozen-in plasma) “convection”. This was also the origin of the concept of magnetic reconnection, made by Jim Dungey in 1953 (published in 1961)."
And as I told Ziggurat, I could go on and on listing examples like those since I only quoted from the first few pages in Google searches numbering 1000's of pages of hits. You totally misrepresent what that mainstream has done vis a vis "open" field lines. And I think you know it.
Furthermore, I can just as easily find scientists stating unequivocally that field lines must be closed loops according to Gauss' law. For example:
http://en.wikipedia.org/wiki/Magnetic_field "Gauss's law for magnetism" states that the magnetic field is solenoidal (has zero divergence). This is equivalent to the simple statement that, in any field-line depiction of a magnetic field, the field lines cannot have starting or ending points; they must form a closed loop, or else extend to infinity on both ends."
http://simple.wikipedia.org/wiki/Maxwell's_equations "The structure of the magnetic field ... snip ... This equation only works if the integral is done over a closed surface. This equation says, that in every volume the sum of the incoming magnetic field lines equuals the sum of the outgoing magnetical field lines. This means that the magnetic field lines must be closed loops."
http://www.yorku.ca/marko/ComPhys/Ampere/Ampere.html "Magnetic field lines are always closed. One can formulate Gauss' law for magnetism, but given that there is no equivalent of charges (permanent magnets are always dipoles), the magnetic flux through closed surfaces always vanishes."
http://farside.ph.utexas.edu/teaching/316/lectures/node78.html "Gauss' Law for Magnetic Fields ... snip ... Magnetic field-lines form closed loops which never begin or end."
http://farside.ph.utexas.edu/teaching/316/lectures/node116.html "Maxwell's Equations ... snip ... The second equation is the magnetic equivalent of Gauss' law (see Sect.*8.10). This equation describes how the non-existence of magnetic monopoles causes magnetic field-lines to form closed loops."
http://books.google.com/books?id=bR...sig=KBXVn0S68FN0msmbpuaMwS1KHxA&hl=en#PPT4,M1 "The Physics Companion by Anthony C. Fischer-Cripps ... snip ... 2003 ... snip ... It is a peculiar property of magnetic field lines that they always form closed loops. ... snip ... 3.7.4 Maxwell's equations ... magnetic field lines always form closed loops. ... snip ... Magnetic field lines always close upon themselves. ... snip ... Gauss' law for magnetism says that for any closed surface in space, the total magnetic flux is zero meaning that all magnetic flux lines join up with themselves."
http://209.85.173.104/search?q=cach...+field+lines"+closed&hl=en&ct=clnk&cd=7&gl=us "Gauss’ Law and Magnetism, Kevin Paulson, Department of Engineering, University of Hull ... snip ... • Magnetic field lines do not begin or end, but always close like a circle."
http://ocw.mit.edu/NR/rdonlyres/ 79E24C10-1A35-4365-856D-A7316B3EBD2E/0/4_05_2002_edited.pdf "April 5, 2002 ... snip ... Gauss’ Law for Magnetic Fields ... snip ... Magnetic Field lines are always closed"
http://books.google.com/books?id=6P...sig=Qbe5ydrn-QQxIF3R1NRHH3bTgsE&hl=en#PPP1,M1 "Introduction to Electromagnetic Compatibility by Clayton R. Paul, Department of Electrical and Computer Engineeering ... snip ... 2006 ... is Gauss' law for the magnetic field, stated in integral form ... snip ... This result implies that all magnetic field lines form closed paths"
http://electron9.phys.utk.edu/phys136d/modules/m7/Ampere.htm "The third of Maxwell's equations tells us that there are no magnetic charges, and therefore no sources and sinks for the magnetic field.* The net flux of the magnetic field through any closed surface is zero.* All the field lines that enter through the surface into a volume enclosed by the surface also exit through the surface. Magnetic field lines always are closed loops."
http://people.rit.edu/agysps/courses/313_062web/exam_info/finalinfo.htm " Final Exam info, Wednesday, 28 Feb 2007 ... snip ... GL for magnetism -- no magnetic monopoles; magnetic field lines form closed loops (pen must stay on paper)"
http://www.phys.uri.edu/~gerhard/PHY204/tsl236.pdf "Gauss' Law for Magnetic Field ... snip ... Magnetic field lines always close in themselves."
http://ww.stjohnshigh.org/~fborchelt/ index_files/ap_physics_chapters_29_30_31.ppt ... snip ... Chapter 29* Magnetic Fields & Forces ... snip ... Gauss’s Law for magnetism is similar, using a Gaussian surface • implies that magnetic field lines MUST be closed loops, not lines, that both enter and exit the Gaussian surface"
http://www.geocities.com/iamlad/physicsmain.html "Lori Dalton's Physics Page ... snip ... Gauss's Law in Magnetism: This equation states that the net magnetic flux through a closed surface is zero. In other words, magnetic field lines do not begin or end anywhere and thus must be looped."
So don't preach to us about the "importance of careful language in physics", ben. Better you spend your time explaining why astrophysicists invented the notion of open field lines while ignoring such known phenomena as Birkeland currents, double layers, exploding double layers and z-pinches. 