## Advances in Differential Equations

- Adv. Differential Equations
- Volume 12, Number 3 (2007), 241-264.

### Instability of vortex solitons for 2D focusing NLS

#### Abstract

We study instability of a vortex soliton $e^{i(m\theta+\omega t)}\phi_{\omega,m}(r)$ to $$iu_t+\Delta u+|u|^{p-1}u=0,\quad\text{for $x\in \mathbb{R}^n$, $t>0$,}$$ where $n=2$, $m\in \mathbb{N}$ and $(r,\theta)$ are polar coordinates in $\mathbb{R}^2$. Grillakis \cite{Gr} proved that every radially symmetric standing wave solution is unstable if $p>1+4/n$. However, we do not have any examples of unstable standing wave solutions in the subcritical case $(p <1+n/4)$. Suppose $\phi_{\omega,m}$ is nonnegative. We investigate a limiting profile of $\phi_{\omega,m}$ as $m\to\infty$ and prove that, for every $p>1$, there exists an $m_*\in \mathbb{N}$ such that, for $m\ge m_*$, a vortex soliton $e^{i(m\theta+\omega t)}\phi_{\omega,m}(r)$ becomes unstable under perturbations of the form $e^{i(m+j)\theta}v(r)$ with $1\ll j\ll m$.

#### Article information

**Source**

Adv. Differential Equations Volume 12, Number 3 (2007), 241-264.

**Dates**

First available in Project Euclid: 18 December 2012

**Permanent link to this document**

https://projecteuclid.org/euclid.ade/1355867464

**Mathematical Reviews number (MathSciNet)**

MR2296567

**Zentralblatt MATH identifier**

1158.35089

**Subjects**

Primary: 35Q55: NLS-like equations (nonlinear Schrödinger) [See also 37K10]

Secondary: 35B35: Stability 35Q51: Soliton-like equations [See also 37K40]

#### Citation

Mizumachi, Tetsu. Instability of vortex solitons for 2D focusing NLS. Adv. Differential Equations 12 (2007), no. 3, 241--264.https://projecteuclid.org/euclid.ade/1355867464