Body
Alfvén wave
An *Alfvén wave* is a wave that occurs in a plasma
<https://www.plasma-universe.com/Plasma> (or conducting fluid),
resulting from the interaction of the magnetic fields and electric
currents <https://www.plasma-universe.com/Electric_current> within it,
causing an oscillation of the ions. Alfvén wrote in a letter to the
journal /Nature/ in 1942:
"If a conducting liquid is placed in a constant magnetic field,
every motion of the liquid gives rise to an E.M.F. which produces
electric currents. Owing to the magnetic field, these currents give
mechanical forces which change the state of motion of the liquid.
Thus a kind of combined electromagnetic-hydrodynamic wave is
produced."^[1]
<https://www.plasma-universe.com/Alfv%C3%A9n_wave#cite_note-alfven1942-1>
Alfvén waves initiated the field of magnetohydrodynamics
<https://www.plasma-universe.com/Magnetohydrodynamics> which
subsequently earned Alfvén a Nobel Prize.
Put some thought behind this statement "A conductive liquid"!!
On 1/10/2019 7:41 AM, Norman Wootan wrote:
>
> https://en.wikipedia.org/wiki/Hannes_Alfv%C3%A9n Please read this mans
> research and see how he was often rejected by fellow physicists.
>
> On 1/10/2019 7:31 AM, Norman Wootan wrote:
>>
>> http://aa.springer.de/papers/7324002/2300449.pdf Still researching
>> the importance of the Alfven waves in plasma.
>>
>> On 1/10/2019 6:51 AM, Norman Wootan wrote:
>>>
>>> Moray, Jon Gentry and Warren asked pertinent questions regarding
>>> velocities, magnetic flux etc. in plasma events so I did a search as
>>> to whether Alfven waves have a frequency. This site pretty well
>>> defines a lot of plasma info that we need. See:
>>> https://www.britannica.com/science/plasma-state-of-matter#ref507092
>>>
>>> On 1/10/2019 6:29 AM, Warren Keillor [email protected]
>>> [EVGRAY] wrote:
>>>> Norman
>>>> Hooper's work looks very compelling. At his time of
>>>> experimentation, super conductors were not a reality as they are
>>>> now. The fact that a resistance free conductor might accelerate a
>>>> potential's velocity, after going through a resistor, suggests an
>>>> analogy to fluid dynamics, much like Bernuili's principle
>>>> application of a venturi to gases.
>>>> The idea of dielectric conductors is a mind smasher, inverting our
>>>> entire circuit thoughts.
>>>> Generally, pretty radical concepts, in a zone to set us up for
>>>> quantum physics thinking. Whew!
>>>> Cheers Warren
>>>>
>>>> Sent from Yahoo Mail on Android
>>>> <https://go.onelink.me/107872968?pid=InProduct&c=Global_Internal_YGrowth_AndroidEmailSig__AndroidUsers&af_wl=ym&af_sub1=Internal&af_sub2=Global_YGrowth&af_sub3=EmailSignature>
>>>>
>>>> On Wed, 9 Jan 2019 at 3:17 PM, Norman Wootan [email protected]
>>>> [EVGRAY]
>>>> <[email protected]> wrote:
>>>>
>>>> Good question Warren! Nobody really knows how the potential and
>>>> current manifest in the conductor passing through a flux field.
>>>> Your question is valid cause there very well may be some sort
>>>> of reconnect occurring here. Theory was, that the flux field
>>>> was photon stream which enabled pairing to produce electrons
>>>> and attending current. There is still so much that we don't
>>>> know but things are getting interesting. Read that last doc
>>>> that I posted for it is very enlightening on this subject.
>>>> See: http://www.tfcbooks.com/mall/more/temp/x565-hen.htm This
>>>> is one of Oles favorites.
>>>>
>>>> On 1/9/2019 9:09 AM, Warren Keillor
>>>> [email protected]
>>>> <mailto:[email protected]> [EVGRAY] wrote:
>>>>>
>>>>> Norman
>>>>>
>>>>> I wonder if, in a down to earth , practical manner, the
>>>>> connect/re-connect plays a role in, for instance, the Kromery,
>>>>> where one slides the magnets at right angles to their locked
>>>>> together state.
>>>>> Initially, I need both hands to grasp the flywheel to turn my
>>>>> Kromery.
>>>>> Once turning, one finger's friction on the rim, easily rotates
>>>>> the flywheel, regardless of the load.
>>>>> Too fast, then eddy currents start warming the magnetic coil
>>>>> cores.
>>>>> Are we cutting those magnetic lines?
>>>>> Cheers Warren
>>>>> Sent from Yahoo Mail on Android
>>>>> <https://go.onelink.me/107872968?pid=InProduct&c=Global_Internal_YGrowth_AndroidEmailSig__AndroidUsers&af_wl=ym&af_sub1=Internal&af_sub2=Global_YGrowth&af_sub3=EmailSignature>
>>>>>
>>>>> On Wed, 9 Jan 2019 at 9:25 AM, Norman Wootan
>>>>> [email protected] <mailto:[email protected]> [EVGRAY]
>>>>> <[email protected]> <mailto:[email protected]>
>>>>> wrote:
>>>>>
>>>>> http://young.caltech.edu/Collisionless_Magnetic_Reconnection.html
>>>>>
>>>>> On 1/9/2019 8:21 AM, Norman Wootan wrote:
>>>>>>
>>>>>> https://phys.org/news/2017-10-hidden-mechanics-magnetic-field-reconnection.html
>>>>>>
>>>>>> On 1/9/2019 8:14 AM, Norman Wootan wrote:
>>>>>>>
>>>>>>> https://gss.pppl.gov/talks/reconnection%20lecture%201.pdf
>>>>>>>
>>>>>>> On 1/9/2019 8:09 AM, Norman Wootan wrote:
>>>>>>>>
>>>>>>>> https://link.springer.com/chapter/10.1007%2F978-94-009-0545-0_14
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Recent
>>>>>>>> Developments
>>>>>>>> in
>>>>>>>> the
>>>>>>>> Theory
>>>>>>>> of
>>>>>>>> Magnetic
>>>>>>>> Reconnection
>>>>>>>> Dieter
>>>>>>>> Biskamp
>>>>>>>> Max-Planck-Institut
>>>>>>>> fiir
>>>>>>>> Plasmaphysik
>>>>>>>> 8046
>>>>>>>> Garching
>>>>>>>> bei
>>>>>>>> Miinchen,
>>>>>>>> Federal
>>>>>>>> Republic
>>>>>>>> of
>>>>>>>> Germany
>>>>>>>> Abstract
>>>>>>>> The
>>>>>>>> talk
>>>>>>>> briefly
>>>>>>>> reviews
>>>>>>>> previous
>>>>>>>> stationary
>>>>>>>> models,
>>>>>>>> mainly
>>>>>>>> configurations
>>>>>>>> of
>>>>>>>> the
>>>>>>>> Petschek
>>>>>>>> type,
>>>>>>>> pointing
>>>>>>>> out
>>>>>>>> their
>>>>>>>> shortcomings
>>>>>>>> and
>>>>>>>> basic
>>>>>>>> failure
>>>>>>>> in
>>>>>>>> accounting
>>>>>>>> for
>>>>>>>> fast
>>>>>>>> magnetic
>>>>>>>> reconnection
>>>>>>>> in
>>>>>>>> the
>>>>>>>> limit
>>>>>>>> of
>>>>>>>> large
>>>>>>>> magnetic
>>>>>>>> Reynolds
>>>>>>>> number.
>>>>>>>> It
>>>>>>>> is
>>>>>>>> shown
>>>>>>>> that
>>>>>>>> in
>>>>>>>> this
>>>>>>>> limit
>>>>>>>> no
>>>>>>>> relevant
>>>>>>>> stationary
>>>>>>>> states
>>>>>>>> exist.
>>>>>>>> Instead
>>>>>>>> strong
>>>>>>>> small-scale
>>>>>>>> MHD
>>>>>>>> turbulence
>>>>>>>> develops
>>>>>>>> even
>>>>>>>> in
>>>>>>>> 2D
>>>>>>>> geometry,
>>>>>>>> giving
>>>>>>>> rise
>>>>>>>> to
>>>>>>>> energy
>>>>>>>> dissipation
>>>>>>>> and
>>>>>>>> reconnection
>>>>>>>> rates
>>>>>>>> independent
>>>>>>>> of
>>>>>>>> the
>>>>>>>> value
>>>>>>>> of
>>>>>>>> the
>>>>>>>> collisional
>>>>>>>> re-
>>>>>>>> sistivity.
>>>>>>>> I
>>>>>>>> Introduction
>>>>>>>> In
>>>>>>>> the
>>>>>>>> last
>>>>>>>> decade
>>>>>>>> it
>>>>>>>> has
>>>>>>>> been realized
>>>>>>>> that
>>>>>>>> the
>>>>>>>> presence
>>>>>>>> of
>>>>>>>> magnetic
>>>>>>>> fields
>>>>>>>> is
>>>>>>>> a
>>>>>>>> ubiquitous
>>>>>>>> phenomenon
>>>>>>>> in
>>>>>>>> cosmic
>>>>>>>> systems.
>>>>>>>> On
>>>>>>>> the
>>>>>>>> one
>>>>>>>> hand,
>>>>>>>> magnetic
>>>>>>>> fields
>>>>>>>> serve
>>>>>>>> as
>>>>>>>> a large
>>>>>>>> energy
>>>>>>>> reservoir
>>>>>>>> which
>>>>>>>> may
>>>>>>>> be
>>>>>>>> tapped
>>>>>>>> in
>>>>>>>> a fast
>>>>>>>> dynamic
>>>>>>>> process
>>>>>>>> leading
>>>>>>>> to
>>>>>>>> various
>>>>>>>> kinds
>>>>>>>> of
>>>>>>>> explosive
>>>>>>>> events
>>>>>>>> such
>>>>>>>> as
>>>>>>>> flares.
>>>>>>>> On
>>>>>>>> the
>>>>>>>> other
>>>>>>>> hand,
>>>>>>>> magnetic
>>>>>>>> fields
>>>>>>>> tend
>>>>>>>> to
>>>>>>>> be
>>>>>>>> compressed
>>>>>>>> in
>>>>>>>> processes
>>>>>>>> such
>>>>>>>> as
>>>>>>>> protostar
>>>>>>>> formation
>>>>>>>> and
>>>>>>>> are
>>>>>>>> computed
>>>>>>>> to
>>>>>>>> dominate
>>>>>>>> the
>>>>>>>> dynamics
>>>>>>>> in
>>>>>>>> the
>>>>>>>> later
>>>>>>>> phases
>>>>>>>> in
>>>>>>>> a nonrealistic
>>>>>>>> way
>>>>>>>> if
>>>>>>>> not
>>>>>>>> dissipated
>>>>>>>> sufficiently
>>>>>>>> fast.
>>>>>>>> To
>>>>>>>> account
>>>>>>>> for
>>>>>>>> such
>>>>>>>> processes of
>>>>>>>> fast
>>>>>>>> magnetic
>>>>>>>> field
>>>>>>>> annihilation
>>>>>>>> is
>>>>>>>> the
>>>>>>>> main
>>>>>>>> objective
>>>>>>>> of
>>>>>>>> the
>>>>>>>> theory
>>>>>>>> of
>>>>>>>> magnetic
>>>>>>>> reconnect
>>>>>>>> ion.
>>>>>>>> The
>>>>>>>> term
>>>>>>>> magnetic
>>>>>>>> reconnect
>>>>>>>> ion
>>>>>>>> refers
>>>>>>>> to
>>>>>>>> the
>>>>>>>> picture
>>>>>>>> of
>>>>>>>> magnetic
>>>>>>>> field
>>>>>>>> lines.
>>>>>>>> These
>>>>>>>> have
>>>>>>>> a well-defined
>>>>>>>> meaning
>>>>>>>> in
>>>>>>>> a highly
>>>>>>>> conducting
>>>>>>>> fluid,
>>>>>>>> viz.
>>>>>>>> thin
>>>>>>>> magnetic
>>>>>>>> flux
>>>>>>>> tubes
>>>>>>>> which
>>>>>>>> are
>>>>>>>> carried
>>>>>>>> along
>>>>>>>> with
>>>>>>>> the
>>>>>>>> fluid,
>>>>>>>> maintaining
>>>>>>>> their
>>>>>>>> individuality,
>>>>>>>> though
>>>>>>>> they
>>>>>>>> may
>>>>>>>> be
>>>>>>>> wound
>>>>>>>> in
>>>>>>>> a very
>>>>>>>> complex
>>>>>>>> manner.
>>>>>>>> Only
>>>>>>>> owing
>>>>>>>> to
>>>>>>>> finite
>>>>>>>> electrical
>>>>>>>> resistivity
>>>>>>>> or
>>>>>>>> some
>>>>>>>> equivalent
>>>>>>>> process
>>>>>>>> may
>>>>>>>> two
>>>>>>>> field
>>>>>>>> lines
>>>>>>>> coming
>>>>>>>> close
>>>>>>>> together
>>>>>>>> lose
>>>>>>>> their
>>>>>>>> identities
>>>>>>>> by
>>>>>>>> being
>>>>>>>> cut
>>>>>>>> and
>>>>>>>> reconnected
>>>>>>>> in
>>>>>>>> a different
>>>>>>>> way.
>>>>>>>> Though
>>>>>>>> this
>>>>>>>> is
>>>>>>>> a local
>>>>>>>> process,
>>>>>>>> it
>>>>>>>> leads
>>>>>>>> to
>>>>>>>> a change
>>>>>>>> of
>>>>>>>> field
>>>>>>>> topology
>>>>>>>> permitting
>>>>>>>> new
>>>>>>>> types
>>>>>>>> of
>>>>>>>> large-scale
>>>>>>>> plasma
>>>>>>>> motions
>>>>>>>> that
>>>>>>>> would
>>>>>>>> otherwise
>>>>>>>> be
>>>>>>>> inhibited.
>>>>>>>> The
>>>>>>>> 255
>>>>>>>> w.
>>>>>>>> BrinbMnn
>>>>>>>> et
>>>>>>>> al.
>>>>>>>> (eds.J,
>>>>>>>> Physical
>>>>>>>> Processes
>>>>>>>> in
>>>>>>>> Hot
>>>>>>>> Cosmic
>>>>>>>> PlIlsmas,
>>>>>>>> 255-269.
>>>>>>>> e
>>>>>>>> 1990
>>>>>>>> Kluwer
>>>>>>>> Academic
>>>>>>>> Publishers.
>>>>>>>> 256
>>>>>>>> change
>>>>>>>> of
>>>>>>>> the
>>>>>>>> magnetic
>>>>>>>> field
>>>>>>>> is described
>>>>>>>> by
>>>>>>>> Faraday's
>>>>>>>> law:
>>>>>>>> oB
>>>>>>>> (
>>>>>>>> ...
>>>>>>>> )
>>>>>>>> 2'"
>>>>>>>> 7it=VX
>>>>>>>> iixB
>>>>>>>> +
>>>>>>>> 'IV
>>>>>>>> B.
>>>>>>>> (1)
>>>>>>>> Here
>>>>>>>> the
>>>>>>>> ratio
>>>>>>>> of
>>>>>>>> the
>>>>>>>> diffusion
>>>>>>>> term
>>>>>>>> and
>>>>>>>> the
>>>>>>>> convection
>>>>>>>> term
>>>>>>>> (2)
>>>>>>>> is
>>>>>>>> a convenient
>>>>>>>> dimensionless
>>>>>>>> measure
>>>>>>>> of
>>>>>>>> the
>>>>>>>> resistivity,
>>>>>>>> Rm
>>>>>>>> being
>>>>>>>> the
>>>>>>>> magnetic
>>>>>>>> Reynolds
>>>>>>>> number.
>>>>>>>> In
>>>>>>>> practically
>>>>>>>> all
>>>>>>>> astrophysical
>>>>>>>> plasmas
>>>>>>>> Rm
>>>>>>>> is large,
>>>>>>>> essentially
>>>>>>>> because
>>>>>>>> of
>>>>>>>> the
>>>>>>>> large
>>>>>>>> scales
>>>>>>>> L.
>>>>>>>> Hence
>>>>>>>> magnetic
>>>>>>>> diffusion
>>>>>>>> is
>>>>>>>> in
>>>>>>>> general
>>>>>>>> a very
>>>>>>>> weak
>>>>>>>> process.
>>>>>>>> Magnetic
>>>>>>>> processes
>>>>>>>> such
>>>>>>>> as
>>>>>>>> solar
>>>>>>>> flares,
>>>>>>>> however,
>>>>>>>> seem
>>>>>>>> to
>>>>>>>> require
>>>>>>>> fast
>>>>>>>> reconnection
>>>>>>>> with
>>>>>>>> time
>>>>>>>> scales
>>>>>>>> practically
>>>>>>>> independent
>>>>>>>> of
>>>>>>>> Rm.
>>>>>>>> The
>>>>>>>> main
>>>>>>>> theoretical
>>>>>>>> problem
>>>>>>>> therefore
>>>>>>>> is
>>>>>>>> to
>>>>>>>> find
>>>>>>>> models
>>>>>>>> allowing
>>>>>>>> sufficiently
>>>>>>>> high
>>>>>>>> reconnect
>>>>>>>> ion
>>>>>>>> rates.
>>>>>>>> Fast
>>>>>>>> reconnection
>>>>>>>> is
>>>>>>>> not
>>>>>>>> a diffuse
>>>>>>>> process,
>>>>>>>> but
>>>>>>>> is
>>>>>>>> strongly
>>>>>>>> localized
>>>>>>>> in
>>>>>>>> current
>>>>>>>> sheets.
>>>>>>>> Such
>>>>>>>> current
>>>>>>>> sheets
>>>>>>>> may
>>>>>>>> arise
>>>>>>>> at
>>>>>>>> any
>>>>>>>> point
>>>>>>>> with
>>>>>>>> non-vanishing
>>>>>>>> magnetic
>>>>>>>> shear
>>>>>>>> and
>>>>>>>> a velocity
>>>>>>>> gradient
>>>>>>>> along
>>>>>>>> the
>>>>>>>> direction
>>>>>>>> of
>>>>>>>> the
>>>>>>>> shear
>>>>>>>> perpendicular
>>>>>>>> to
>>>>>>>> the
>>>>>>>> field,
>>>>>>>> i.e.
>>>>>>>> virtually
>>>>>>>> everywhere
>>>>>>>> in
>>>>>>>> the
>>>>>>>> plasma,
>>>>>>>> as
>>>>>>>> visualized
>>>>>>>> in
>>>>>>>> Fig.
>>>>>>>> 1.
>>>>>>>> The
>>>>>>>> simplest
>>>>>>>> models
>>>>>>>> are
>>>>>>>> quasi-stationary
>>>>>>>> configurations
>>>>>>>> with
>>>>>>>> one
>>>>>>>> current
>>>>>>>> sheet
>>>>>>>> at
>>>>>>>> a well
>>>>>>>> defined
>>>>>>>> location
>>>>>>>> determined
>>>>>>>> by
>>>>>>>> the
>>>>>>>> overall
>>>>>>>> geometry,
>>>>>>>> which
>>>>>>>> have
>>>>>>>> been
>>>>>>>> investigated
>>>>>>>> in
>>>>>>>> the
>>>>>>>> conventional
>>>>>>>> theory
>>>>>>>> of
>>>>>>>> magnetic
>>>>>>>> reconnection.
>>>>>>>> The
>>>>>>>> basic
>>>>>>>> assumption
>>>>>>>> in
>>>>>>>> these
>>>>>>>> theoretical
>>>>>>>> approaches is
>>>>>>>> the
>>>>>>>> existence
>>>>>>>> of
>>>>>>>> a two-dimensional
>>>>>>>> subsystem
>>>>>>>> around
>>>>>>>> an
>>>>>>>> X-type
>>>>>>>> magnetic
>>>>>>>> neutral
>>>>>>>> point
>>>>>>>> which
>>>>>>>> is
>>>>>>>> small
>>>>>>>> compared
>>>>>>>> with
>>>>>>>> the
>>>>>>>> global
>>>>>>>> magnetic
>>>>>>>> configuration
>>>>>>>> but
>>>>>>>> large
>>>>>>>> compared
>>>>>>>> with
>>>>>>>> the
>>>>>>>> so-called
>>>>>>>> diffusion
>>>>>>>> region
>>>>>>>> around
>>>>>>>> the
>>>>>>>> neutral
>>>>>>>> point,
>>>>>>>> where
>>>>>>>> the
>>>>>>>> diffusion
>>>>>>>> term
>>>>>>>> in
>>>>>>>> (1)
>>>>>>>> is
>>>>>>>> important.
>>>>>>>> In
>>>>>>>> this
>>>>>>>> subsystem
>>>>>>>> conditions
>>>>>>>> would
>>>>>>>> rapidly
>>>>>>>> adjust
>>>>>>>> to
>>>>>>>> changes
>>>>>>>> in
>>>>>>>> the
>>>>>>>> global
>>>>>>>> configuration,
>>>>>>>> so
>>>>>>>> that
>>>>>>>> the
>>>>>>>> evolution
>>>>>>>> of
>>>>>>>> the
>>>>>>>> latter
>>>>>>>> would
>>>>>>>> correspond
>>>>>>>> to
>>>>>>>> a sequence
>>>>>>>> of
>>>>>>>> stationary
>>>>>>>> states
>>>>>>>> in
>>>>>>>> the
>>>>>>>> former
>>>>>>>> which
>>>>>>>> are
>>>>>>>> steady-state
>>>>>>>> solutions
>>>>>>>> with
>>>>>>>> the
>>>>>>>> boundary
>>>>>>>> conditions
>>>>>>>> determined
>>>>>>>> by
>>>>>>>> the
>>>>>>>> global
>>>>>>>> system.
>>>>>>>> This
>>>>>>>> is
>>>>>>>> the
>>>>>>>> idea
>>>>>>>> of
>>>>>>>> stationary
>>>>>>>> forced
>>>>>>>> reconnection.
>>>>>>>> The
>>>>>>>> prototype
>>>>>>>> of
>>>>>>>> such
>>>>>>>> configurations
>>>>>>>> is Petschek's
>>>>>>>> reconnection
>>>>>>>> model
>>>>>>>> 1),
>>>>>>>> which
>>>>>>>> is given
>>>>>>>> schematically
>>>>>>>> in
>>>>>>>> Fig.
>>>>>>>> 2.
>>>>>>>> In
>>>>>>>> fact,
>>>>>>>> much
>>>>>>>> of
>>>>>>>> the
>>>>>>>> theoretical
>>>>>>>> work
>>>>>>>> on
>>>>>>>> magnetic
>>>>>>>> reconnection
>>>>>>>> 2
>>>>>>>> ),3)
>>>>>>>> consists
>>>>>>>> of
>>>>>>>> modifications
>>>>>>>> and
>>>>>>>> refinements
>>>>>>>> of
>>>>>>>> this
>>>>>>>> model.
>>>>>>>> The
>>>>>>>> theory
>>>>>>>> is based
>>>>>>>> on
>>>>>>>> the
>>>>>>>> effect
>>>>>>>> that
>>>>>>>> the
>>>>>>>> motion
>>>>>>>> of
>>>>>>>> a plasma
>>>>>>>> may
>>>>>>>> be
>>>>>>>> supersonic
>>>>>>>> at
>>>>>>>> arbitrarily
>>>>>>>> low
>>>>>>>> speed
>>>>>>>> with
>>>>>>>> respect
>>>>>>>> to
>>>>>>>> the
>>>>>>>> slow
>>>>>>>> mode
>>>>>>>> . Hence,
>>>>>>>> by
>>>>>>>> analogy
>>>>>>>> with
>>>>>>>> a system
>>>>>>>> of
>>>>>>>> two
>>>>>>>> supersonic
>>>>>>>> gas
>>>>>>>> jets
>>>>>
>>>>