Structure of warm-up field in liquids near bottom of channel and share of energy, walking on the evaporation.
Will Value first temperature of overheat of water
under the channel. As far as energy on the evaporation is deliver to the border to the
account of heat conduction from the depth of liquid, possible value a gradient of
temperature near of borders dT/dZ , Z - the coordinate in
depth of liquids, ensuring density of heat 
flow on the vaporization:
, where x - the heat conduction of water:
.
For the expected value q @ 1000 Wt \ cm × cm will have
dT/ dZ @ 130000
degree/cm .
For rough evaluation will take that maximum of warm-up profile in
liquids happens to approximately on depth of penetration
of light Z@ a - 1 , where a - a factor of absorbing a light in water
(a @ 5 00/ cm
- on the length of wave 10,6 mkm). Then for temperature in
maximum an will have
that answers an enourmous overheat (near critical temperature
of water
T = 374° C under the atmospheric
pressure) Pic.7a.
This evaluation is uprate on two reasons. As far as in experiment
near of
the bottom of channel are obviously observe turbulent moving a
liquid -
(Photo d,b), the heat
conduction can be realize in turbulent mode, i.e. efficient factor of the thermal
diffusivity
,
where DV
- a distinctive scale of the turbulent fluctuation of the velocity of flow, l - distinctive (maximum) amount of turbulence. Upper border
for 
1cm /sec
× 0.1@ 0.1 cm ×
cm / sec , that on two orders above the heat conduction of
water. So at presence of the turbulent
transfer are potentially possible reduce an overheat of liquid
before » 2,5° .Other mechanism, not allow observable
overheat, is ablation away heats from the area heat release by the convection flows
downwards from the point of channel - refer to Pic.2. Follows to notice
that value 
gives a share of
energy , walking upwards, i.e. to surfaces of evaporation, and are consumption on the
vaporization. Exactly this part of the heat release
accounts for the area Z< Zn , where flow of heat is direct
to surfaces. Remaining
portion of the select heat , account for Z< Zn , leaves
downwards and disperses on heating up of the main mass of liquid,rather then on its evaporation. On experimental given this
share » 0.5, that allows to expect that Zn » 1.The most,stabilization of overheat must occur, mainly, to the account of
turbulence, rather then the convection ablation of the
heat.
The radiation screen by vapours a water.
As far as in the experiment less
than 25% lazer power disperses on the evaporation and heating
of liquid, possible expect that before the surface of
bottom reaches only small share of powers of lazer bunch. Value a possibility an the
radiation screen a ferry in the most channel and on the route from
the lens before the surface of water.
Factor of absorbing molecular
pair nongreat (a @ 0.0005·1/ cm - under
P
@ 1atm), that gives very small values of
absorbing ~ 0.01 , that can not explain an observed effect.
However, necessary to take into consideration, that vapour,
moving on the increase crater, is coolled and so it is condense. As
shown in the book [4], for the pair in the
manner of drops with the amount ~
10 mkm (order of wavelength) each droplet absorbs and diffuses practically all fall
on
it radiation. Using results [4 ], possible value a
factor of absorbing a pair a n as follows: 
, where a -absorbing factor of water., r -
density a pair, density a water = 1g /cm3 , x - a share of a condensation pair , Rk - a radius
of drop of a condensation part. Under r ~ 0.001 g / cm3
and x ~ 1 for a n will have evaluation a n ~ 0.1
× 1 / cm . This means that big part of the
light will absorption on the distance ~10cm.
Thereby , the screen is wholly possible.
Since this fact is confirm in following
experiments , we see a natural way of raising efficiency of lazer influence on the liquid an airflow route of spreading a ray from the lens before
the surface. Possible hope that îáäóâà
routes will sufficiently, to raise efficiency before limiting, as far as condensation will
occur, mainly, outside of the steam channel, where
vapour inheres under the action of powerful irradiating - 1000 Wt / cm× cm , under which
condensations effectively prevents an evaporation of drop ( bleaching
aerosol) by the powerful
light influence. Time lifes dripped under such influence
~ 0.01 sec, that corresponds to the order a time of the passage of gas on the channel.
