We discovered a new type of spiral wave solutions in reaction-diffusion systems -spike spiral wave, which significantly differs from spiral waves observed in FitzHugh-Nagumo-type models. We present an asymptotic theory of these waves in Gray-Scott model. We derive the kinematic relations describing the shape of this spiral and find the dependence of its main parameters on the control parameters. The theory does not rely on the specific features of Gray-Scott model and thus is expected to be applicable to a broad range of reaction-diffusion systems. PACS Number(s): 03.40. Kf, 05.70.Ln, 82.20.Mj, 82.40.Bj Formation of rotating spiral waves (rotors) is one of the most vivid and ubiquitous phenomena of nonlinear physics [1][2][3][4][5][6][7][8][9][10][11]. These waves are observed in nonlinear optical media [12], chemical reactions of BelousovZhabotinsky type, catalytic reactions on crystal surfaces [5][6][7], and in a variety of biological systems: social amoebae Dictyostelium discoideum [13], Xenopus oocytes [14], chicken retina [15], and the heart of animals and man, where the formation of spiral waves is responsible for cardiac arrythmias and the life-threatening condition of ventricular fibrillation [1,11].A generic model used to describe spiral waves is a pair of reaction-diffusion equations of activator-inhibitor type [1-10]where θ is the activator, i.e., the variable with respect to which there is a positive feedback; η is the inhibitor, i.e., the variable with respect to which there is a negative feedback and which controls activator's growth; q and Q are certain nonlinear functions representing the activation and the inhibition processes; l and L are the characteristic length scales, and τ θ and τ η are the characteristic time scales of the activator and the inhibitor, respectively; and A is the bifurcation parameter. A considerable amount of studies was done on the excitable systems with FitzHugh-Nagumo-type kinetics (N-systems) (see, for example, [1-8] and references therein). These systems are described by Eqs. (1) and (2) with L = 0, and the nonlinearity in q such that the nullcline of Eq.(1) is N-or inverted N-shaped. Theory of the spiral waves in N-systems with α = τ θ /τ η ≪ 1 was recently developed by Karma [16,17].The existence of spiral waves in excitable N-systems is due to the ability of such systems to sustain traveling waves, the simplest of which is a solitary wave -traveling autosoliton (AS) [1][2][3][4][5][6][7][8][9][10]. In N-systems the equation q(θ, η, A) = 0 has three roots: θ i1 , θ i2 , and θ i3 , for fixed A and η = η i . For α ≪ 1 an AS consists of a front, which is a wave of switching from the stable homogeneous state θ = θ h and η = η h to the state with θ = θ max (θ h = θ i1 and θ max = θ i3 for η i = η h ) whose width is of order l, and a back of width of order l that follows the front some distance w ≫ l behind the front. Thus, in the AS the distribution of θ is a broad pulse, while the value of η slowly varies from η = η h to some value η = η m in the back of the pulse, a...