Upload
others
View
3
Download
0
Embed Size (px)
Citation preview
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Stability of Periodic Motions in SatelliteDynamics
Stability Theory for Hamiltonian Systems
Boris S. Bardin
Faculty of Applied Mathematics and PhysicsDepartment of Theoretical Mechanics
Course of Computer Algebra and Differential Equations
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Contents
1 Stability of Hamiltonian systems with more then two degreesof freedom
Stability for most initial conditionsFormal stability
2 Stability of Relative Equilibrium Positions of Satellite in aCircular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Stability for most initial conditionsFormal stability
Contents
1 Stability of Hamiltonian systems with more then two degreesof freedom
Stability for most initial conditionsFormal stability
2 Stability of Relative Equilibrium Positions of Satellite in aCircular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Stability for most initial conditionsFormal stability
Arnold’s Theorem of Stability for most of initialconditions
Let us consider a Hamiltonian system of k degrees of freedom.The Birkhoff normal form of the Hamiltonian
H = H(0)(r) + H(1)(r,ϕ), (1)
where
H(0)(r) = ω1r1 + · · ·+ ωk rk +k∑
i,j=1
aij ri rj ,
and H(1)(r,ϕ) are terms of the order higher then two withrespect ri .
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Stability for most initial conditionsFormal stability
Arnold’s Theorem of Stability for most of initialconditions
If at r1 = · · · = rk = 0 Hamiltonian (1) satisfy the condition ofnondegeneracy
Dk = det(∂2H0∂r2
)6= 0 (2)
or the condition of isoenergetic nondegeneracy
Dk+1 = det
(∂2H0∂r2
) (∂H0∂r
)(∂H0∂r
)0
6= 0, (3)then the Hamiltonian system is stable for most of initialconditions (in the sense of Lebesque measure).
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Stability for most initial conditionsFormal stability
Arnold diffusion
Conditions (7) and (8) are not the same.
Example: H(0) = ω1r1 − ω2r2 + (r1 + r2)2
D2 = 0, D3 = −2(ω1 + ω2)2 6= 0.
The stable for most of initial conditions system can be unstablein the sense of Liapunov. Such a phenomenon is called Arnolddiffusion.
The typical case in higher-dimensional problems is topologicalinstability.Arnold’s example (Dokl. Acad. Nauk SSSR, V.156, 1964, 9-12):
H =12(I21 + I
22) + ε(cosϕ1 − 1)(1 + µ(sinϕ2 + cos t))
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Stability for most initial conditionsFormal stability
Nehoroshev’s Theorem
The KAM theory proves the metric stability, i.e stability for mostof initial conditions
Nehoroshev’s TheoremSuppose that the unperturbed Hamiltonian H(0)(I) is a steepfunction. Then for a sufficiently small perturbation
|I(t)− I(0)| < εb for 0 ≤ t ≤ 1ε
exp(
1εa
)in the perturbed Hamiltonian system. Here a and b are positiveconstants that depend on the geometric properties of theunperturbed Hamiltonian.
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Stability for most initial conditionsFormal stability
Arnold diffusion in resonant casesMarkeev’s Example
Let us consider the system with Hamiltonian
H = ω1r1 − ω2r2 + ω3r3 + r1r3 − r1r2 + r2r3 + H(1)(r,ϕ),
whereH(1)(r,ϕ) = r1r2
√r3 sin(2ϕ1 + 2ϕ2 + ϕ3).
and resonance 2ω1 − 2ω2 + ω3 = 0 takes placeThe conditions of Arnold’s theorem are fulfilled
D4 = (ω1 + ω2)2 6= 0,
but the Hamiltonian system has the following solution
2ϕ1 + 2ϕ2 + ϕ3 = π
r3(t) =12
r1(t) =12
r2(t) = r3(0)[1− 6r32
3 (0)t ].
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Stability for most initial conditionsFormal stability
Contents
1 Stability of Hamiltonian systems with more then two degreesof freedom
Stability for most initial conditionsFormal stability
2 Stability of Relative Equilibrium Positions of Satellite in aCircular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Stability for most initial conditionsFormal stability
Formal stability
Definition: If there exist power series
G(q,p) = G2(q,p) + G3(q,p) + . . . ,
such that it is a formal positive definite integral of theHamiltonian system
dqdt
=∂H∂p
,dpdt
= −∂H∂q
, (4)
then system (4) is called formal stable.
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Stability for most initial conditionsFormal stability
Moser’s Theorem on Formal stability
Let us consider a Hamiltonian system of k degrees of freedomwith the Hamiltonian.
H = ω1r1 + · · ·+ ωk rk + H(1)(r,ϕ), (5)
here H(1)(r,ϕ) are terms of the order higher then one withrespect ri .If the following conditions
n∑i=1
miωi 6= 0, mi ∈ Z, mi ≥ 0,n∑
i=1
mi > 0
are fulfilled, then the system with Hamiltonian (5) is formalstable.(Moser, J. New aspects in the theory of stability of Hamiltoniansystems. Comm. Pure Appl. Math. V.11, 1958, 81–114.)
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Stability for most initial conditionsFormal stability
Glimm’s Theorem on Formal stability
Let us suppose that the normal form of the Hamiltonian reads
H = ω1r1 + · · ·+ ωk rk +k∑
i,j=1
aij ri rj + H(1)(r,ϕ), (6)
andn∑
i=1
miωi 6= 0, mi ∈ N, 0 <n∑
i=1
|mi | ≤ 4.
If the quadratic formk∑
i,j=1
aij ri rj is definite, then the system with
Hamiltonian (6) is formal stable.(Glimm, J. Formal stability of Hamiltonian systems. Comm.Pure Appl. Math. V.17, 1964, pp. 509–526.)
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Stability for most initial conditionsFormal stability
Brjuno’s Theorem on Formal stability
If the quadratic formk∑
i,j=1
aij Ii Ij 6= 0,
for the vector I = (I1, . . . , Ik ) 6= 0 such that Ii ≥ 0 and Ii aresolutions of the equation
n∑i=1
mi Ii = 0,
then the system with Hamiltonian (6) is formal stable.
(Brjuno, A. D. Formal stability of Hamiltonian systems.(Russian) Mat. Zametki V.1, 1967, pp. 325–330.)
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Contents
1 Stability of Hamiltonian systems with more then two degreesof freedom
Stability for most initial conditionsFormal stability
2 Stability of Relative Equilibrium Positions of Satellite in aCircular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Relative Equilibrium Positions of Satellite in a CircularOrbit
Orbit of the mass center n
v
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
The Hamiltonian of the Problem
H =(sin2 ϕ+ θA cos2 ϕ)
2 sin2 ϑp2ψ +
[(sin2 ϕ+ θA cos2 ϕ) +
θAθC
]p2ϕ2
(cos2 ϕ+ θA sin2 ϕ)p2ϑ2− (sin2 ϕ+ θA cos2 ϕ)pψpϕ+
(1− θA) sin 2ϕ2 sinϑ
pψpϑ −(1− θA)
2sin 2ϕ cotϑpψpϕ − pψ
32
[θA − 1θA
a211 +θC − 1θA
a213
]
where
a11 = cosψ cosϕ− sinψ sinϕ cosϑ, a13 = sinψ sinϑ
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Variations
Parameters: θA = A/B and θC = C/BEquilibrium position:
ψ = ϕ = pϑ = pψ = 0, ϑ =π
2, pψ =
1θA
Let us introduce variations
q1 = ϑ−π
2, q2 = ϕ, q3 = ψ,
p1 = pϑ, p2 = pϕ, p3 = pψ −1θA
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Perturbed Hamiltonian
H = H2 + H3 + H4 + . . .
H2 =p212
+θA
2θCp22 +
12θA
q21 −(θA − 1)(3θA + 1)
2θ2Aq23+
+ q1p2 −θA − 1θA
q2p1 +θA2
p23 +3(θC − θA)
2θA
H3 = q21p3 +3(θA − 1)
θAq1q2q3 + θAq1q2p3 −
3θA − 1)θA
q22q3−
− (θA − 1)q2p1p3
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Contents
1 Stability of Hamiltonian systems with more then two degreesof freedom
Stability for most initial conditionsFormal stability
2 Stability of Relative Equilibrium Positions of Satellite in aCircular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Linear Problem of StabilitySufficient condition of stability
If the following condition is fulfilled
θA < θC < 1
then relative equilibrium is stable in Lyapunov sense.
Sufficient condition of stability: If the biggest principal axis isdirected along the radius vector of the center of mass and thesmallest one is directed along the normal of the orbit.
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Linear Problem of StabilityNecessary condition of stability
If parameter values belong to the Domain I then relativeequilibrium is stable in linear approximation.In domain II
H =12ω1(q21 +p
21)−
12ω2(q22 +p
22)+
12ω2(q23 +p
23)+H3+H4+ . . .
where ω1 > 0, ω2 > 0, ω3 > 0. Nonlinear study isnecessary to solve stability problem.
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Contents
1 Stability of Hamiltonian systems with more then two degreesof freedom
Stability for most initial conditionsFormal stability
2 Stability of Relative Equilibrium Positions of Satellite in aCircular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Nonlinear Problem of StabilityNonresonant case
In polar variables: qi =√
2ri sinϕi , pi =√
2ri cosϕi
H = H(0)(r1, r2, r3) + H̃(r1, r2, r3, ϕ1, ϕ2, ϕ3)
where
H(0) = ω1r1 − ω2r2 + ω3r3++ c200r21 + c110r1r2 + c101r1r3 + c020r
22 + c101r1r3 + c002r
23
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Stability for most of initial conditions
In Domain II outside of curves of resonances up to fourth orderat r1 = r2 = r3 = 0 Hamiltonian (1) satisfy the condition ofnondegeneracy
D3 = det(∂2H0∂r2
)6= 0 (7)
or the condition of isoenergetic nondegeneracy
D4 = det
(∂2H0∂r2
) (∂H0∂r
)(∂H0∂r
)0
6= 0, (8)Thus, the Hamiltonian system is stable for most of initialconditions (in the sense of Lebesque measure).
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Formal Stability
If in the domain ri ≤ 0 (i = 1,2,3) the system of equations
ω1r1 − ω2r2 + ω3r3 = 0c200r21 + c110r1r2 + c101r1r3 + c020r
22 + c101r1r3 + c002r
23 = 0
does not have any solution except trivial one r1 = r2 = r3 = 0,then the equilibrium is formal stable.
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Resonances
In the considered approximation the following resonances cantake place
k1ω1 − k2ω2 + k3ω3 = 0 (|k1|+ |k2|+ |k3| = 2,3,4)
List of resonances which should be taken into account:
1. ω1 − ω2 − 2ω3 = 0, 2. ω1 − ω2 − ω3 = 0,
3. ω2 − ω3 = 0, 4. ω1 + ω2 − 2ω3 = 0,
5. ω1 − ω3 = 0, 6. 2ω2 − ω3 = 0,
7. ω1 + ω2 − ω3 = 0, 8. ω1 − 3ω2 = 0,
9. 2ω1 − ω3 = 0,
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Arnold Diffusion
In points Pi (i = 1,2,3) of the Domain II the fifth orderresonance 4ω2 = ω1 takes place.Equality 16c020 + 4c011 + c002 = 0 is fulfilled
The Hamiltonian normal form reads
H = H(0) + γi r22√
r3 cos(4ϕ2 + ϕ3) + O((r1 + r2 + r4)3)
The truncated system has the following partial solution
r1 = 0, r2 = 4r3 > 0.
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability of Relative Equilibrium Positions of Satellite in a Circular Orbit
Hamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability
Arnold Diffusion
Boris Bardin
Stability of Hamiltonian systems with more then two degrees of freedomStability for most initial conditionsFormal stability
Stability of Relative Equilibrium Positions of Satellite in a Circular OrbitHamiltonian of the Perturbed MotionLinear Problem of StabilityNonlinear Problem of Stability