In the mathematics of dynamical systems, the **double-scroll attractor** (sometimes known as **Chua's attractor**) is a strange attractor observed from a physical electronic chaotic circuit (generally, Chua's circuit) with a single nonlinear resistor (see Chua's Diode). The double-scroll system is often described by a system of three nonlinear ordinary differential equations and a 3-segment piecewise-linear equation (see Chua's equations). This makes the system easily simulated numerically and easily manifested physically due to Chua's circuits' simple design.

Using a Chua's circuit, this shape is viewed on an oscilloscope using the X, Y, and Z output signals of the circuit. This chaotic attractor is known as the double scroll because of its shape in three-dimensional space, which is similar to two saturn-like rings connected by swirling lines.

The attractor was first observed in simulations, then realized physically after Leon Chua invented the autonomous chaotic circuit which became known as Chua's circuit.^{[1]} The double-scroll attractor from the Chua circuit was rigorously proven to be chaotic^{[2]} through a number of Poincaré return maps of the attractor explicitly derived by way of compositions of the eigenvectors of the 3-dimensional state space.^{[3]}

Numerical analysis of the double-scroll attractor has shown that its geometrical structure is made up of an infinite number of fractal-like layers. Each cross section appears to be a fractal at all scales.^{[4]} Recently, there has also been reported the discovery of hidden attractors within the double scroll.^{[5]}

In 1999 Guanrong Chen (陈关荣) and Ueta proposed another double scroll chaotic attractor.^{[6]}

Chen system:

Plots of Chen attractor can be obtained with Runge-Kutta method:^{[7]}

parameters:a = 40, c = 28, b = 3

initial conditions:x(0) = -0.1, y(0) = 0.5, z(0) = -0.6

## Contents

## Multiscroll attractors

Multiscroll attractors also called *n*-scroll attractor include the Lu Chen attractor, the modified Chen chaotic attractor, PWL Duffing attractor, Rabinovich Fabrikant attractor, modified Chua chaotic attractor, that is, multiple scrolls in a single attractor.^{[8]}

### Lu Chen attractor

An extended Chen system with multiscroll was proposed by Jinhu Lu (吕金虎）and Guanrong Chen^{[9]}

Lu Chen system equation

parameters：a = 36, c = 20, b = 3, u = -15..15

initial conditions：x(0) = .1, y(0) = .3, z(0) = -.6

### Modified Lu Chen attractor

System equations:^{[9]}

In which

params := a = 35, c = 28, b = 3, d0 = 1, d1 = 1, d2 = -20..20, tau = .2

initv := x(0) = 1, y(0) = 1, z(0) = 14

### Modified Chua chaotic attractor

In 2001, Tang et al. proposed a modified Chua chaotic system^{[10]}

In which

params := alpha = 10.82, beta = 14.286, a = 1.3, b = .11, c = 7, d = 0

initv := x(0) = 1, y(0) = 1, z(0) = 0

### PWL Duffing chaotic attractor

Aziz Alaoui investigated PWL Duffing equation in 2000：^{[11]}。

PWL Duffing system:

params := e = .25, gamma = .14+(1/20)*i, m0 = -0.845e-1, m1 = .66, omega = 1; c := (.14+(1/20)*i)，i=-25..25;

initv := x(0) = 0, y(0) = 0;

### Modified Lorenz chaotic system

Miranda & Stone proposed a modified Lorenz system:^{[12]}

parameters： a = 10, b = 8/3, c = 137/5;

initial conditions： x(0) = -8, y(0) = 4, z(0) = 10

## References

**^**Matsumoto, Takashi (December 1984). "A Chaotic Attractor from Chua's Circuit" (PDF).*IEEE Transactions on Circuits and Systems*. IEEE. CAS-31 (12): 1055–1058.**^**Chua, Leon; Motomasa Komoru; Takashi Matsumoto (November 1986). "The Double-Scroll Family" (PDF).*IEEE Transactions on Circuits and Systems*. CAS-33 (11).**^**Chua, Leon (2007). "Chua circuits". Scholarpedia. Bibcode:2007SchpJ...2.1488C. doi:10.4249/scholarpedia.1488.**^**Chua, Leon (2007). "Fractal Geometry of the Double-Scroll Attractor". Scholarpedia. Bibcode:2007SchpJ...2.1488C. doi:10.4249/scholarpedia.1488.**^**Leonov G.A.; Vagaitsev V.I.; Kuznetsov N.V. (2011). "Localization of hidden Chua's attractors" (PDF).*Physics Letters A*.**375**(23): 2230–2233. Bibcode:2011PhLA..375.2230L. doi:10.1016/j.physleta.2011.04.037.**^**Chen G., Ueta T. Yet another chaotic attractor. Journal of Bifurcation and Chaos, 1999 9:1465.**^**阎振亚著 《复杂非线性波的构造性理论及其应用》第17页 SCIENCEP 2007年**^**Chen, Guanrong; Jinhu Lu (2006). "GENERATING MULTISCROLL CHAOTIC ATTRACTORS: THEORIES, METHODS AND APPLICATIONS" (PDF).*International Journal of Bifurcation and Chaos*.**16**(4): 775–858. Bibcode:2006IJBC...16..775L. doi:10.1142/s0218127406015179. Retrieved 2012-02-16.- ^
^{a}^{b}Jinhu Lu **^**Chen, Guanrong; Jinhu Lu (2006). "GENERATING MULTISCROLL CHAOTIC ATTRACTORS: THEORIES, METHODS AND APPLICATIONS" (PDF).*International Journal of Bifurcation and Chaos*.**16**(4): 793–794. Bibcode:2006IJBC...16..775L. doi:10.1142/s0218127406015179. Retrieved 2012-02-16.**^**J.Lu et al p837**^**J.Liu and G Chen p834