[en] Using a one-dimensional electromagnetic particle code which simulates self-consistently the full ion and electron dynamics, we study instabilities driven by energetic ions injected continuously in a plasma where the density and the lower-hybrid resonance frequency ω_LH increase with time. The simulation shows that the ion cyclotron harmonic wave with ω ≃ lΩ_i, where l is an integer and Ω_i is the ion cyclotron frequency, is excited when ω_LH becomes close to lΩ_i. When ω_LH is greater than lΩ_i, this wave couples with the ion Bernstein mode that has the dispersion curve connecting to ω_LH. It is also found that as a result of the instabilities and the wave-wave coupling, the stair-like frequency chirping with the riser Ω_i appears in the magnetic fluctuations in the frequency range of ω_LH. The frequency chirping has characteristics similar to the frequency chirping observed in the RF radiations at the plasma start-up phase of the LHD experiments. (author)