Journal of Applied Mathematics and Physics, 2013, 1, 37-46
http://dx.doi.org/10.4236/jamp.2013.13007 Published Online August 2013 (http://www.scirp.org/journal/jamp)
Random Attractors for the Dissipative Hamiltonian
Amplitude Equation Governing Modulated Wave
Instabilities with Additive Noise*
Jinyan Yin, Yangrong Li, Huijun Zhao
School of Mathematics and Statistics, Southwest University, Chongqing, China
Email: yjy111@swu.edu.cn, liyr@swu.edu.cn, huijun88@swu.edu.cn
Received June 10, 2013; revised July 15, 2013; accepted September 10, 2013
Copyright © 2013 Jinyan Yin et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
In this paper, we study the random dynamical system (RDS) generated by the dissipative Hamiltonian amplitude equa-
tion with additive noise d efined on the periodic boundaries. We inv estigate the existence o f a compact random attractor
for the RDS associated with the equation through introducing two functions and one process in . The com-
pactness of the RDS is established by the decomposition of solution semigroup.
1
0
EHL
2
Keywords: Random Dynamical System; Random Attractor; Hamiltonian Amplitude Equation
1. Introduction
The Hamiltonian amplitude equation
2
i2
xtt
 
 0
, (1)
was first proposed by Tanaka, Yajima and Wadati as a
model for the nonlinear modulation of stable plane wave
in unstable media [1,2]. In 1992 as an improved version
of (1), the equation
2
i2 0,0
xtt xt
 
 1
, (2)
was proposed [3], which generalized (1) in the sense that

,; 0,
x
t
 
xt
, (3)
but one can show that for most initial data

0
lim, ;,
x
tx

t, (4)
even if the two functions agree at t = 0. Both of these
models can be derived systematically from more com-
plicated Hamiltonian systems through a particular limit-
ing process (nearly monochromatic waves of small am-
plitude) corresponding to 0
. Even so, keeping
0
in (2) is crucial because (1) is formally integrable
but ill-posed, whereas (2) is a generalization of it which
is apparently not integrable but well-posed.
In this paper, we consider the following dissipative
Hamiltonian amplitude equation governing modulated
wave instabilities perturbed by an additive white noise

2
1
i
t txtxxx
m
jj
j
duudtudtudtudtfuudt
hdW
 
 
(5)

0
,,,
t
ux uxuxux

1
, (6)
and the periodic boundary condition

,u xLtu xLt
,, (7)
where is an unknown complex valued function, is
the unit of imaginary number, the internal
ui
,
I
LL ,
,
and
are positive constants, which satisfy
, the functions , , are
time independent, the random functions

2
j
hHI1,2, ,jm
W,
1, 2j,,m
, are independent two-side real-valued
Wiener processes on a probability space
,,
F
P
which will be specified later, and

f
s is ,
1
C
s
fs
is real valued function which satisfies that
2
C
0
1
lim inf0,,1
s
Fs s
s

  
, (8)
0
1
lim inf0,,1
s
sfsF ss
s


 
*This work is supported by National Natural Science Foundation o
f
China (11071199) and Natural Science Foundation of Chongqing
(2009BB8105).
, (9)
C
opyright © 2013 SciRes. JAMP
J. Y. YIN ET AL.
38
where 01
, 0
is a constant depended on
and
, and
 
s
d
F
sf
tt.
The deterministic case has been studied extensively,
for instance, Guo, B. L. and Dai, Z. D. [4] proved that
there exists a global weak attractor 1
in 1
EHH
21
is actually a global strong attractor in 1
E.
Dai, Z. D. [5proved the existence of a global attractor
0
in 12
0
EH
, ande equality 01
for (5) and it] obtained t
Lh
 .
Dai, Z. DL. Huang, J. [6] obtained a global at-
tractor for the unperturbed system in 0
E and 1
E re-
ctivelyng, L., Dai, Z. D. [7] obtained the estimate
of the Hausdorff dimension and the fractal dimension of
a global attractor for the perturbed and unperturbed sys-
tems separately. However, up to the best of our knowl-
edge, the research for the dissipative Hamiltonian ampli-
tude equation governing modulated wave instabilities
with random attractors has not in volved.
Recen
. Yang,
. Yaspe
tly, many authors have studied the existence of
ra
ollows. In Section 2, for
co
ndom attractors for other equations [8-10]. In this paper,
for (5), we first obtain an absorbing set in 0
E and 1
E
respectively through introducing two functio and o
process, then by the decomposition of solution semi-
group we derive the compactness in 0
E. As far as we
know, no one has studied stochastic eations through
introducing two functions, so this method enriches the
study of stochastic equations.
This paper is organized as f
ns ne
qu
nvenience of the reader, we recall some basic notions
on function spaces and the theory of random dynamical
system. In Section 3, we solve Equation (5) and get the
corresponding RDS
. In Section 4, we prove the exis-
tence of a random attractor in 0
E for this RDS.
Throughout this paper, we adopt the following nota-
tions. We write

22
LLI,

11
H
HI,

22
H
HI fo dr short. Weenote byand
d
the norms,
by


, an
, the inner prodts in 1
uc
H
and
2
Lrespectively. We lso use au to denote the dular
absolute v a lue of u. mo
or
2. Preliminaries
all some basic notions on function
2.1. Function Spaces and Operators
g for (5). Let
In this section, we rec
spaces [4,7], the theory of RDS [11-14] and introduce the
method of the existence of random attractors for the con-
tinuous RDS [8,10], which we will use in this paper.
We first consider the mathematical settin
2
L, 1
H
, 2
H
be usual Sobolev space, 12
0
EHL
,
H nd

T
,uv
. We define the f
ts and norately:
for any

T
0
,
i
uv E
 and
2
scalar p
1
a
uc
1
EH
rod ollowing
rms sepa
ii

T
0
,uv E, we
have
0
1212 12
,,
Euu vv


,
,
0
22
Euv
,
2
for any

T
1
,
iii
uv E
and , we ve

T
1
,uv E
 ha

11 22
EDu Du,
22
12 1
,,,v v

1
222
uv
E

Let
212
:2
A
DDA HHL , then
A
is a
positive self-adjoint operator, which has the firsigen-
value
t e
1
2
inf u
.
12
uH u
2.2. Random Dynamical Systems
Let
,,
F
P be a probability space and
:
tR
be a family of measur
ch that

,t
t
,
trans su
t 
formations e preserving

is measurable,
0id
and tst s

for all ,
s
tR. The flow t
together with rresponding probability space theco
,,,
t
F
 is called a measurable dynamical system.
2.2.1 A continuous random dynamical sys- Definition
tem(RDS) on a Polish space

,
X
d with Borel
-algebra on
,,,
t
F
 is a measurable map
:RX
,

,, ,tx tx
X

such that ..as
1)
,id
on
X
0
;
2)
t

,,,
ssts

 
, for all ,
s
tR
(cocyc
3) le property);
,:t

random compac
is continuous.
is a family of
co
A t set


K

mpact sets indexed by
such thevery xat for
the
mapping
,xdxK
is measurable wipect
to th res
F
.
Lt
ebe a random set and B . We say
s B if attract
lim,,0,. .
ta s
 
 t
dist t

 ,
where
,dist
denotes the Hausdorff semi-distan in ce
X
. We say
absorbs B if there exists
0
such thall

B
tt
B
tat for
,
,.
 
, .
t
t s

a
 .
A random set is said to be a randoctor
fo m attra
r the RDS
i..asf
1)
i a randomompact set; s c
2)
is invariant, that is,
,t
t
)(
3)

 for all t0;
attracts all deterministicn bouded sets
eore pact set
ab
B.
Thm 2.2.2 If there exists a random com
sorbing every bounded set Bthen the RDS
possesses a random attractor
,
 

 ,
Copyright © 2013 SciRes. JAMP
J. Y. YIN ET AL. 39

0,
:ts t
st


 
 where is tomega-limit set
oe the Equation and Generate a RDS
he
of B.
3. Slv
We consider the probability space

,,
F
P, where
m



12
,,,0 0
mCR

 ,
, :R
and
F
is the Borel
-
, while
algebr a induced by the co mact
opeology ofis the corresponding
p
Wie-n top
ea P
ner msure on
,
F
. Then, we identify
with
 


12
,, for
m
WtWtWtttR
.
 
,W t
Finally, we define the time shift by
,
 
ttt
 
 
,
a
tR
ontin
. Then
system. om dy-
namical system urpose,
w
dimensional Ornstein-Uhlenbeck
eq
One may easily check that a solut
by
Putting

,,,ttR
F
is a metric dynamical
cuous rand
corresponding to (5). For this p
We now want to establish
e need to convert the stochastic equation with an addi-
tive noise into a deterministic equation with a random
parameter.
Given 1,2,,jm, consider the stochastic station-
ary solution of the one-
uation

jj j
dzz dtdWt
 . (10)
ion to (10) is given



ed,
tts


. (11)
jj
ztWs tR

1
m
j
j
j
zh
z, by (10) we have
1
m
j
j
th dW
.
j
dz zd
We also need two facts



2021
ed0
2



, (12)
as
2
00
jj
Ez Ez
 . We also have

lim j
t
zt
t
 0,. .as (13)
Assumed . Then
ding theorem

2
j
hDAH
,

by Sobolev embed-

21
H
ICI, we have
1
j
hCI.
In particular, all
j
Dh are bou
ts a 00nded continuous functions.
Thus there exis
(dly onepending on
j
h)
such that
 
01
sup
xI Dz
,,,. .
m
j
j
xtzttRa s

(14)
where
j
j
zhz and
j
z is the Ornstein-Uh
process defined by (11). It is also easy to prove that
lenbeck

211
m
j
j
zD zt
, (15) zD z
where only depends on
j
h.
a ran
10
To sat (5) generates dom
tem, we let
how th dynamical sys-

vtu tutzt
 ,
atis es
wher e is
t
the solution of (5), then u, v sfiu, t
u
 

 
2
010
,
,
,,, ,
t
t
uvu
vAuuvi
 

 
x
xx
z
u
vzzfuu
uuvuuz
 

 
 


(16)
where 1
0
uH, 2
0
vL
, and
0



T
00
,,uv
0
E


proof as .
dete
rministic case [4], one can
et that
By the same
easily gfor ..sa
,
, the following results
hold
sa
Theorem 3.1 If

T
00 0
,uv E, there exists a unique
solution

T
0
, ,tu E

 of (16),
which

,tvt
 
,
tisfies
1
,;CT H

, ,ut


,,vt C
2
;T L
.
If

T
00 1
,uv E
, there exists a unique solution
E
 

T
1
,,vt
 
 
,,tut
isf of (16), which saties
2
;uxH,

,,t CT

1
,,;vtCT H

.
the solution of From the above discussion, we denote
(5) by
0 ,;,ut utu

(denote sometimesby
,
0
;,ut u
;ut
,
,ut
,

ut or even if no
E by
u
confusions). Then we can define a mapping
:R
00
E
00
,:,;0,tt



00
,;0,;0, , 0,utuv t

, ,vt
, (17)
by the definition 2.2.1, it is easy to show that
is a
continuous RDS onwith the following fact
0
E
 
00
,0,;,
 
,
for


T
,, ,0.uv E

00
00

4. Random Attractors
ng Set in 4.1. Absorbi
E
0
In this subsection, we prove that the RDS
defined by
rb set , which
. Recall that
(17) has a bounded absoing
absorbs, in fact, all the bounded sets

0
BE
i
0
BE
 

T
000
, ;,, ;,,, ;,tutuvtv
 
s the solu-
tion of (16) with
0
uu
and
vuuzv

10 0
 .
We then rewrite (16) as follows
C
opyright © 2013 SciRes. JAMP
J. Y. YIN ET AL.
40
 
,LF u

T
,,,,,,vt
 
 
 
,
(18)
where
,
u
v




II
L
A
II
 


 

,
 

2
,
xx x
z
Fiuvzzfu
  



u

.
We now can prove the absorption of RDS
(defin
by (17)) in .
Lemma 4.1or any no random bounded , there
ex
ed
0
E Fset B
ists a random variable
10

satisfying the fol-
lowing property: for every

T
u B
 ere
ex 01
,uu 0, th
ists

1
B
T
 , such that, for any
B
T
, the
following estimate holds

..as
0
01
;, ,
E


Proof. Taking the innu
, 1,0tt.
er prodct of (18) with
in
, we obtain that
0
E


,,
,
2d LF
t
2
1d
 
 . 19)
Taking the real pa
(
rt of (19), we find that












22 2
2
2d
Re ,
t
uv v
  
 
2
1d 1Re ,
Re,Re,Re ,
Re ,Re,Re,
xx
x
uv uuv
zuiu vv v
zvz vfuuv

 

 

 
. (20)
Since




 

22
1Re ,
1Re ,
1d 11Re
2d
t
uv
uuu z
uu
t
,
uz



, (21)
and





 

2
2
22
22
Re ,
2
2
,
Re ,Re ,Re ,
1d dRe ,Re ,
2d
t
t
fu uv
fu uuuzRe










22 2
2
2
2
d11
d
d22 2
Re ,
Re, Re,
Re,Re ,Re,
Re, 0
x
x
uvFuxu
t
uvv
iuvfuuu
uzzvz v
fu uz

  
 


 


 
 


2
. (23)
We introduce two functions


22 2
111
,d
222
g
uvuvFux

, (24)
 



f
uuufuuu fuuz
F
uxfuuufu uz
t

 
 
,
(22)
it follows from (20)-(22), we get that





22
1
2
2
,Re,
Re, Re,
Re,Re,Re,
Re ,
x
x
Guv uuvv
iuvfuu
uzzvz v
fu uz
  
 

 
 

, (25)
an
u
d one process
 
11
m
j
j
Ct zt
.
So that (23) gives
(26)
 
11
d,,
dguv Guv
t0
. (27)
In the following, we denote byany constant depend-
ing only on the data c
,,,,,
I
f
th
s

e or even ine
positive contant
, which can be dif-
ferent from line to linsame line. Now we
xists can prove there e0
, d and 1
d
such that
 
101
22
1
,
d
uv

1
1
,,
2
2
Guv guv
C tgtc

 
, (28)

2
1
1,d
g
2
uv c
, (29)
where 1
is defined by (15) and

g
t will be defined
in the following p ap er, henc e we o btain
 
101 1
d,,,
d
g
uvguvu

. (3 ) v
t0
In fact we ha ve











101 1
22
222
00
,,,
Re,
Re ,
Re ,Re,22
x
x
Guv guvuv
uuvv
iuvfu
zvfu uz

  
 
 

 
 

(31)
22
dux.
2
0dR
e, Re,
2Fu xuzzv


u v
C
opyright © 2013 SciRes. JAMP
J. Y. YIN ET AL. 41
By estimating every terms on the right side in (31), let-
ting
1
21
23


, (32)
where 1
is the first eigenvalue of
A
, then by (32), we
find
that




22
2222
2
2
1
22
2
Re ,
3Re,
4224
242 24
33
2242 2
242
24 2
3
uuvv
uvvuuv
vuvvu
uvvuvv
uvvuv
vu uv
  
   

 
 

 
 

 

 


 


 
22
222
33
2
   


2
22

222
33
42
u
 

2
2
222
222
3
22
33
422 22
3
422
v
uvvuv
uvv

 





 




,
(33)
and


22
22 22
Re, 1
1
22
x
iuv uv
uv
 



. (34)
Using
f
uniform l y bounded, we get





   
   




2
2
22
11 11
11 11
22
2
11 11
11 11
1
2
11
1
222 2
2
11 1
Re ,Re,Re ,Re,
44
44
4444
24444
x
xL
uzzvz vfuuz
zuzvz vfuuz
Ct Ct
Ctu Ctv
Ctc Ct
CtvCt
u Ct
c
Ct


 

 




 
 
 







22
2
u
22 2
22
11
2c
Ct v


 
2222
11
1
4444
c
g
tC





.

11
2
11
2,
Ct
Ct gt


(35)
where t
Taking and

22
0
21


, , such that 02
0
where
isned in (32), and letting defi
00
min ,d

(36)
we find that
22 0
31
42 2
d

 
2
, (37)
0
22222
d

 . (38)
Noting that 011
24
, by (8) and (9), we have
22222
f
00
ddd
2
uuxFuxux



, (39)
using


1
222
1
122
0d
11
ux
1
d2 dux Dux
1
0
2D



,
wh

ere 0
is any positive number. Choosing

1
1
0
0
21
d
 


,
we find that
22 2
dd
xuc.
02
u

(40)
Combining (31)-(40), we infer that
  
22
1
Gu 0
1 11
,, 2
2
d
vguvCtgtc

 .
(41)
In order to prove (29), and similarly to (40), we have

22
11
,22
g
uvuv c
. (42)
ng Taki
1min,1d
, we get (29).
From (r that 27)-(30), we infe
 
2
101 11
d,,2
d
g
uvguvCtg tc
t


. (43)
Taking 4
max ,4



, we have
 

10111
,,
d
 
d
g
uvCtg u
t

v gt c
 . (44)
C
opyright © 2013 SciRes. JAMP
J. Y. YIN ET AL.
42
Putting
 
101101
1
m
j
j
ft Ctzt

  ,
th
(45)
en by the Gronwall Lemma, we get, fo r t




1d
11
00
,e ,
tt
f
guvguvg


1d
e d
tfss
c
.

(46)
In particular, we have, for
1, 0t, 1
 ,






01
01
d
11 100
0d
1
,e,
ed
f
fss
guv cguv
cg c

,


(47)
where 0
1ec
10, , in view of the following fact: for
t
 
 
00
111
000
101
0
ddd
dd d
eee
ee ee
tt
t
fff
ff


 
 

 

.
To estimate all integration terms on the righ
(47), we choos e t side in
0
such that
 
0
11 1
1
00
2
m
j
j
ECE z
 

.
This is possible since by (12), 0

10EC as
. Thus, since

j
zt ry
get is stationaic, it and ergod
is easy to
 
0
1101
1
limd 02
fEfEC
0
1
0
 
 
(48)
ps th
(49)
By (13),

,
which imlieat

01d
lim e0,. .
fas




0
j
z
as
, thus
Ct
1
further

and
g
t is atst 1-times p moolynomoal growth at
, whether with (49), implies that
..as (50)
an
 ich, tog
 


01
0d
1ed,
fss
qgc
 

 
d also implies that



012
d
2
q
1
supe fz



. (51)
Noting that


222
100 0 00
11
,d
222
g
uvuvFux

,

0010
,uuu z


2
,
and , we get
1
0
uH, 1
uL

2
100 0
,1guvc
llow
, (52)
then it fos from (29) and (47)-(52), we obtain that






0
01
01
0
2
22
d
10
10
d
1
2
e1
ed
.
E
f
fss
cc uu uz
cg cc




2
1,;,
dt

0
 
 
We now take
(53)
  

0
22e

11
2
11
2
2c
cq cq
dd
 

and choose
B
T
such that

0122
d
010
e1
fuuu

,
for all
B
T
, then we get



1,0. (54)
0
22
01
,;, ,
E
tt
 

4.2. Absorbing Set in
E
1
In order to prove the absorption property in , we also
need the following change for (18).
Differentiating (18) with respect to
1
E
x
and letting
x
u
,
v
,


T
T
,,
xx
uv

 , we have
 

T
,,
,,,,,
F
t

,
L

 

(55)
where

II
L
A
II
 

 

,



 
2
2
,
.
x
xxx xx
z
iz
zfu
u fu
22
u
2
fu
F

  


 


We now can prove the absorption of RDS
(defined
by (17)) in 1
E.
Lemma 4.2 For anyded set B, there
atisfying th
no random boun
exists a random variable se fol-
lowing property: for ev there
exists

20

ery 01
,


T
0

B,
1
B
T
B
T
, such that, for any
, the
followingolds estimate h..as

1
02
,;,, 1,0.
E
tt
 

Proof. Taking the inner product of (55)ith w
in
, we obtain that
0
E
C
opyright © 2013 SciRes. JAMP
J. Y. YIN ET AL. 43


2
1d ,,
2d LF
t,
 
 . (56)
Taking the real part of (56), we find that








 



22
2
Re ,Re ,,
Re,Re, .
xxx
xxx
zz uu
fu
222
2
2
2
1d 1Re ,
2d
e,Re ,
Re
t
i
f
fuu
 
Re ,
Re ,Rz
  
 
 
 


 

(57)
Due to
 





 


22
1d 11
Re,
2d z
t

  

,58)
1Re ,1Re ,tx
x
z


(
and

 





22 22
222 22
222 222
22
Re, Re,
1d dRe
2d
Re dd
Re, ,
tx
t
t
x
fu ufu uz
d
f
uuxfuuux
t
f
uuuuxfuux
fu uz







 



(59)
and


 

 
22
2222
22 2
Re ,Re ,
1d dRed
2d
dRe,.
tx
t
x
fu fu z
f
uxfu uux
t
fuxfu z


 




(60)
view of (57)-(60), we get that In








 





 
 
22 222
22 2
2
22
22 222
222 22
22 2
d11
d22 2
1Re ,
2
Re ,Re,
Re ,Re,Re,
2Red Re
dRe ,
dRe, 0.
xx
xxx
t
x
x
fu udx
t
fu dx
zi
zzfuu
d
t
f
uuux fuuuux
fu uxfu uz
fuxfu z
 


 

 
 


 
 



 
(61)
Letting



22 222
2
22
11
,d
222
1d
2
g
fu ux
fux
 

(62)
and





 









2,

22
22
2
2
222 222
22 22
2
Re ,Re ,
Re,Re ,Re,
Re, 2Red
Re dd
Re ,d
Re ,
x
xx xx
t
t
x
x
G
z
izz
fuufuuu x
fuuuux fuux
fu uzfux
fu z

 
 



 


 



(63)
Then it comes from (61)-( 63) that
 
22
d,,
dgG
t
 
0
. (64)
ilarly to the above arguments (Lemma
wrove that there exist
Now sim
e can p4.1),
20
, and
, such that 20d
30d
  
222
22
2
211
,,
,2
2
Gg
dCtgt c
 
 
0
 
, (65)

2
3
2,2
d
g
c
 
, (66)
where 1
followi
is defined by (15) and will be defined
in the ng paper, therefore we)(
0tg
have
 
222 2
d,,
dgg
t,
 
. (67)
In fact,












 
 

2222
22
22 2
222
22
222
22
,,,
Re ,
Re,Re,Re ,
2Red
Re, 22
d
22
xxx
tt
x
Gg
izz
22
Re , Re,
xx
zf
uu
22
Red
22
2 22
22
dRe ,
d
x
f
uuux fuu
ffu z
fu ux

 
 

 
uux
fu uxfu uz
u x
 
 




 
 


 



22
d.fu x
(68)
C
opyright © 2013 SciRes. JAMP
J. Y. YIN ET AL.
44
2
, 2
d 0
, d respectivelyTaking are the same as
in (36) and using
, t
u, u
,
f
,
f
,

22
uf
 and uniformly boun in time, we ma-
uded
joring every term on the right side in (68) to get



22
222 2
2
222 2
2
222 2
2
1
222
Re ,
3
4224
3
Re ,22
3
4224
3
22
3
4224
3
22
3,
422
 
 
 

 
  
 

 
  
 
 

 

 


 




 








(69)
where
is defined by (32) and 1
is the first eigen-
value of
A
, and whae ve
22
, 1
  
22 22
1
x

Re
4
i


(70)
and

,

 


 
   
  
 
 
222
22
2
22
22
11 11
11 11
22
11 11 11
22 2
2
11 11
2
11 0
Re,Re ,Re,
Re, Re,
||
2
84
4
284 4
2,
xx xx
xx
xx xx
xx
LL
zz z
fuzfuuz
zz z
fuzf uuz
Ct Ct
Ct Ct
Ct CtcCt
Ctc Ct
Ct gt
 

 

 
 
 

 




 
 
 
 





(71)
where
 
22 2
011
84 4
g
tcCt


.
By


4
12
23
x
Lc

22
222 2
Re ,
,
4
L
fuu
fu uc

 

(72)


4
22
22 2
2
2Red
28
t
t
LL
L
fuuu x
d
fu uuc
2

and young inequality, we have
2


, (73)


4
222
22 22
2
Re d
8
t
t
LL
L
fuu uux
d
fuu uuc
2




, (74)


4
222
2
22 22
22
d
2
28
L
L
fu ux
d
fu uc

2





 


, (75)


4
22
2
22 2
22
d
2
28
L
L
fux
d
fu c

2





 


. (76)
it follows from (68)-(76) that Then
 
 
222
22
2110
22
2110
,,
2
2
2
2
Gg
dCtgt c
dCtgt c
 
2

 
 
 
. (77)
Similarly, with

3min ,1d
, we can easily derive
that

2
3
2,2
d
g
c
 
. (78)
From (64)-(67), we inf e r that
 
2
222 110
d,,2
d
g
gCtg
t
 
tc

(79)
it follows from (44) that, for the sam
,
e
, we have
 

 
221120
d,,
d
g
Ct gg
t

t c
 
(80)
Putting
.
 
221121
1
m
j
j
f
tCt
 
  zt
then by the Gronwall Lemma, we have, for
, (81)
t



2d
2200
,e ,
f
gg





2d
0ed
t
t
tfss
gc
.

(82)
C
opyright © 2013 SciRes. JAMP
J. Y. YIN ET AL. 45
1, 0t , 1
, The same as (47), we have, for






02
02
d
21 200
0d
10
,e ,
ed
f
fss
gcg
cg c

 


(83)
where 2
1ec
, and
 

0
10
edc




2
0d
fss
qg , (84)



022
d
21
supe f
x
qz



. (85)
Noting that



200
22 222
00 000
22
22
2
100
,
11 d
d
2
g
f
uux
fux

 

,


0010
,x
z

,
we get


2
200 0
,gc

1
, (86)
then from (66) an d (83)- (86), we ob t ai n that






02
0d
ed
fss
cg c

0
02
2
20
222
d
1010
10
,;,
2
e()1
E
f
x
dt
cc z
c


 


. (87)
We now take
 

2
2
212
22
2e 2
2c
cq cq
dd




B
T
and choose
such that


0222
d
010
e1
f


 ,
for all

B
T
, then we get



1
22
02
,;t
,, 1,0
Et
 
. (88)
4.3. The Compactness in
E
0
In this subsection, we prove the compactness in
through the decomposition of solution semigroup.
Let be a solution of (5) with initial value
0
E

ut
0
u


T
01
,uu z
 
12
utyt, w


y t . We make the ecomposition
here d

1
y
t and

2
y
t satisfy
and
 
11 11
1011
0,
,,,
t txtxx
t
dyydtydtydtiydt
yx uxyx u
 

  


1
,
x
x (89)


11
,,
.
yxLt yxLt


 

2
,

22222
2
1
22
2
,
,0, ,0,
,.
t txtxxx
m
j
j
j
t
dyy dtydtydtiydt
f
uudt hdW
yxyx
yxLt
 

 


 
(90)
Lemma 4.3 For any no random bound
have, for a ny
yxLt
ed set B, we
0

T
1 0
,uu uB


0
3
222
1111
22
10
0000
2e
t
E
Yyyy
uuu


, (91)
and there exists a random variable
0
1
d
30

such that
..as
for



0
22
22
0,; ,,DY Y3
E


, (92)
spect-
Proof. Taking the
whose initial va afte
putation similarly as Lemobtain (9
Taking the inner product of (90) with
where

T
1111
,t
Yyy y
 and

T
222
,Yyy yz
 satisfy (89) and (90) re
2
inner product of (89) with 1
Y in
lue is

T
0
u
r a simple
t
tively.
0
E
com 01
,uu ,
ma 4.1, we 1).
2
A
Y in 0
E


T
0, z
,
ma 4.2, we
whose initial value is after a s
putation similarly as Lemobtain imp
(92). le com-
Let
12
B
be the ball of of random
ble
21
1
EH H
varia
30

21
10
H E
. Frombedding the compact em
21
EH HL
, we see that
12
B
is
comp random bact. For any noounded set
B
of , pick
0
E
any
tB
. Fr0,
t

om Lemma 4.3, we have
21
00YY
12
0B
 , where
,t
2
Y
is
giveereforen by Th Lemma 4.3., again by Lemma 4.3,
 
 


3
0
2
222
010
1
inf00
2e,0.
E
Euuu
d


0
12
0
1
0
B
Y
 
So

12
,, 0,as.
t
disttB Bt
 

Corolla ry 4.4 The RDS

,t
associated with (17)
pact set possesses a uniformly attracting com
12 0
BE

,t
.2, Lem
, so the RDS is uniformly asymp-
totically compact in
By applying Th 2.2ma 4.1
obtain the final con this whole pa per .
4.5 Assum
S
0
E.
eorem and corollary
4.4, weclusion of
Theorem e

j
hDAHH, then
the RD
12
modeling
po
the dissipative Hamiltonian am-
plitude equation governing modulated wave instabilities
ssesses a compact random attractor

which
C
opyright © 2013 SciRes. JAMP
J. Y. YIN ET AL.
Copyright © 2013 SciRes. JAMP
46
att 2
racts all bounded sets of 1
0
EHL
, “So
.
dati, “Solitons in
e Physical Society
. J. Ablowitz,
ation Governing M
the Ph
. 1187-1193.
.
5.
ou
M. Tanaka an d N. Ya ji
nt
Vol. 94, 1988, pp. 138-162
[2] T. Yajima and M. Wa an Unstable
dium,” Journal of thof Japan, V
1987, pp. 3069-3081.
[3] M. Wadati, H. Segur and MA New Ham-
tonian Amplitude Equodulated W
tabilities,” Journal of ysical Society of Japan
Vol. 61, No. 4, 1992, pp
Acknowledgements
The authors would like to express their sincere thanks to
theonym/her valuable ans referee for his comments
and suggestions toimprove the paper.
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