4th annual leif meeting, 4th annual leif meeting, belfast, july 2003 belfast, july 2003 ions and...

www.physik.tu-ilmenau.de/exp2/home.htmwww.physik.tu-ilmenau.de/exp2/home.htm 4th annual Leif Meeting,4th annual Leif Meeting,

Belfast, July 2003Belfast, July 2003

Ions and Highly Charged Particles in the AtmosphereIons and Highly Charged Particles in the Atmosphere

Thomas Leisner, Technische Universiät Ilmenau, Germany

- The global electrical circuit

- The Role of Charges in the Climate System

- The Stability of Highly Charged Droplets

- Laboratory Experiments on Charged Levitated

Droplets



Anthropogenic climate change ?



The 11 year sunspot cycle



Correlation between cosmic rays and cloud coverage

adapted from H. Svensmark, Phys. Rev. Lett. 81, 5027, (1998)

symbols : cloud coveragesolid line: cosmic rays



Simplified global electrical circuit

+

+

+

+

+

+

+

- -

-

-

-

-

-

-Earth~105 Cb

+ ++

Galactic cosmic rays (GCR)

-+

Solar magnetosphere and solar wind

Auroral currents

Energeticmagnetosphericelectrons

-

+ + ++ +

+

-

- -

E~100V/m

++--

+



solar windactivity

cosmic raysmagnetosph. particles

atmospheric current density

cloud space charge

highly charged evaporation residues (good ice nulei)

electroscavenging enhances ice formation

radiation transportand cloud albedo

precipitation andlatent heat release

atmospheric temperature and dynamics

obse

rved

cor

rela

tions

A connection between solar wind activity and climate?

space weather and atmospheric electricity

cloudmicrophysics

atmosphericphysics



y

z

x

z0

r0

WtV )cos(

0z

Wg

Q

m

Cloud microphysics in the laboratory

feedbackcontrol

CCDarray

W



Experimental

r

z

x

y



Climate chamber and levitator periphery



Connection to the Raman microscope (Yobin Yvon)



Connection to the Bruker IFS 66 FTIR with IRscope II



Determination of size and index of refraction

84 86 88 90 92 94 96

0.0

0.2

0.4

0.6

0.8

1.0

0.0

0.2

0.4

0.6

0.8

1.0

parallel

ligh

t in

ten

sity

(n

orm

aliz

ed

un

its)

scattering angle / deg

perpend.

r= 19.973 µm, n=1.4087



Freezing phase transitions in droplets

0.0 0.5 1.0 1.5 2.0 2.5-4-3-2-10

0.16 s

ln N U / N 0

Time [Seconds]

-1 0 1

~ 500 µs p- pol s- pol

t2

t1

I sca

tt. /a

rb u

nits

time / s



0.0 0.5 1.0 1.5 2.0 2.5-4

-3

-2

-1

0 T=237 Kln(N

u/N

0) = -J(T) V t

ln N

U /

N0

V t1 [cm3 s]

Determination of the nucleation rate



236.00 236.25 236.50 236.75 237.00 237.25

1x106

1x107

1x108

1x109

Our Measurements DeMott und Rogers '90 Pruppacher '95

J /

cm-3 s

-1

Temperature / K

Homogeneous nucleation rates of water

Journal of Chemical Physics, 111, 6521, (1999)Journal of Molecular Liquids 96-97, 153 (2002)



Dynamics of highly charged droplets

thunderstorms are the generators of free charges in the atmosphere

most of the mechanisms for charge separation include collisionsbetween droplets or ice crystals

- -

-

-

+ +++++

~100 V/m

10 kV/m

100 kV/m



A mechanism of charge separation in thunderstorm clouds

T=-20°C

+

+

+

+

+

+--

-T= 0°C

-

-

-

++

+

+

+T=-20°C

Supercooled cloud dropletnucleation starts on surface

Theromodiffusion leads tocharge separation

Outer shell splinters carrypostitive charge upward



0 5 10 15-5.5

-5.0

-4.5

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

T=250 K

r=19µm

r=49µm

ln(N

u/N

o)

time /s

1.096.2

/ln

/ln

21

21 rr

JJ

Is homogeneous freezing of water a surface or bulk process?



Stability of highly charged droplets

3

02

2

32

162

1

R

Ql

R

ll

the frequency of mode l is given by:1

64 30

2

2

R

QX

The quadrupole oscillation (l=2)is unstable if the fissillity:stability is determined by interplay

between surface energy and coulombenergy. Lord Rayleigh 1882:

Though a quadrupole deformation would ultimately lead to symmetric fission, LordRayleigh did predict an asymmetric disintegration of the droplet:

If ... (X>>1)... the liquid is thrown out in fine jets, whose fineness however has a limit" Philosophical Magazine, XIV, 184, (1882)

(Rayleigh did not mention the X=1 case)



Coulomb- instability of an evaporating droplet

0 100 200 300 4000.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

char

ge [

pC]

time /s

drop

let r

adiu

s m



Fast microscopy of the disintegration process

Trigger and delay unit

Fast flashlamp

Photo-multiplier cw laser beam

Long working distance microscope

CCDcamera

Image processor

phase functionmeasurement

injector



Rayleigh jets

Nature, Jan. 9, 2003

100µm

Fast microscopy of the disintegration process

t=0 t=130µs t=153µst=152µs

t=154 µs t=155 µs t=158 µs t=160µs t=165µs t=170µs t=180µs t=200µs

t=140µs t=145µs t=150µst=135µs



Droplet geometry during instability

140 160 180 200 2200.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

time (µs)

asp

ect r

atio

0

20

40

60

80

100

120

140

160

180

tip

angl

e / d

egre

e

jet visible



Summary of Observations

• in one event the total charge loss is 30%, mass loss about 0.3%

• initially the droplets deform ellipsoidally (X=1, l=2 is unstable)

• when an aspect ratio of 3.5 is reached, two sharp tips are formed at the poles

• when the tip angle drops below 60° a fine jet is emitted from each tip

• the jet is emitted within 5µs, with speed up to 50m/s

• each jet disintegrates into roughly 50 small daughter droplets, 1.5 µm in diameter

• the dynamics is remarkably independent of size and surface tension



Acknowledgement

Ilmenau

TU Ilmenau Klaus HemmelmannAndreas RichterDenis DuftRene MüllerTobias Achtzehn

Collaboration:

Claude Guet, CEA Paris

Bernd Huber,CEA Caen



Simulation of the jet breakup

v0= 5m/s

v0= 50m/s



Light scattering from an oscillating droplet:

0 2 4 6 8 10 0 2 4 6 8 10

dri

ve

fie

ld

a d

time / ms

inte

nsi

ty o

f sc

att

ere

d li

gh

t

b e

c f

x

y

Laser

Phys. Rev. Lett., (accepted)



1940 1950 1960 1970 1980 1990 2000

0

200

400

600

sunspots

Rel

ativ

e su

nsp

ot

num

ber

Year

cosmic ions

Rel

ativ

e co

smic

ray

flux

neutrons

Correlation between solar wind activity and cosmic rays

adapted from H. Svensmark, Phys. Rev. Lett. 81, 5027, (1998)



Terrestrial Effects of Space Weather

Aurorae

Geomagnetical storms effect communication and navigation

Satellite damage

Radiation hazards to flight personnel

Climate effects?



solar windactivity

cosmic raysmagnetosph. particles

atmospheric current density

cloud space charge

highly charged evaporation residues are good ice nulei

electroscavenging enhances ice formation

radiation transportand cloud albedo

precipitation andlatent heat release

atmospheric temperature and dynamics

obse

rved

cor

rela

tions

adapted from B.A. Tinsley, Space Science Review 94 , 215, (2000)

A connection between solar wind activity and climate?



Light scattering from an oscillating droplet

0 2 4 6 8 10 0 2 4 6 8 10

dri

ve

fie

ld

a d

time / ms

inte

nsi

ty o

f sc

att

ere

d li

gh

t

b e

c f

x

y

Laser

Phys. Rev. Lett., (accepted)



260 280 300 320 340 360 380 400 420

0

1

260 280 300 320 340 360 380 400 4200

1

2

3

4

5

6

pha

se s

hift

/ra

d

time after injection/s

time of disintegration

A

mp

litu

de [n

o. o

f M

ie r

eso

nan

ces]

The instability occurs at X=1 !

0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.050.0

0.5

1.0

1.5

2.0

2.5

x=1

phas

e sh

ift /

rad

f issility x

0.0

0.2

0.4

0.6

0.8

1.0

am

pl. /

arb

. uni

ts

experiment theory

PRL 89, 084503, 2002



Light scattering during Coulomb instability

-6 -4 -2 0 2 4 60.00

0.05

0.10

0.15

0.20

0.25

sc

atte

rin

g c

ross

se

ctio

n (

arb

. un

its)

time relative to instability [ms]



le

l

d

r x

y

d*

An anayltical shape class for spindle like objects

V: spindle volume: aspect ratio: relative displacement of the generating ellipse (tippedness of the shape)

221 elxdxy

3

1

21

1

Vd

2232312 1arcsin11

1

arctan2

with:



Droplet geometry during instability

140 160 180 200 2200.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

time (µs)

asp

ect r

atio

0

20

40

60

80

100

120

140

160

180

tip

angl

e / d

egre

e

jet visible



Open questions

• How universal is the phenomenon (temperature, size, surface tension, viscosity)

?

• Is it possible to induce the instability below X=1 ?

• Is the ejected material from the droplet surface ?

• Is this process a relevant source of atmospheric nuclei ?



Forced oscillations of incompressible viscous droplets

0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.050.0

0.5

1.0

1.5

2.0

2.5

x=1

phas

e sh

ift /

rad

f issility x

0.0

0.2

0.4

0.6

0.8

1.0

am

pl. /

arb

. uni

ts

l

llRZl

1122 3

0

l

RM l

50

212

412

0

lll

XRCl

tCCZM llllllll cos0

XllR

RVlQ ll 4214

120

02

0

Vibration of mode l is governded by:

With the effective dynamic parameters:

nach R. W. Hasse, Annals of Physics, 1975, 93, 68

30

2

2

64 R

QX



Does the solar activity cycle influence the earth climate?



Types of solar activity

Solar Wind: Quiet particle stream

Flare: Explosion on Sun surface

Protuberance: Ejection of particles from the sun surface

CME: Coronal mass ejection: Ejection of plasma from the corona



Ions and Highly Charged Particles in the AtmosphereIons and Highly Charged Particles in the Atmosphere

Thomas Leisner, Technische Universiät Ilmenau, Germany

- The Stability of Highly Charged Droplets

- Experiments on Single Levitated Droplets

- The Electrical State of the Atmosphere

- The Role of Charges in the Climate System

4th annual leif meeting, 4th annual leif meeting, belfast, july 2003 belfast, july 2003 ions and...

Documents

annual leif meeting

vm slide

experimental slide

levitator periphery

year sunspot cycle slide

charged particles

cloud albedo precipitation

cloud coverage solid