### Narrowband Spikes Observed During the 13 June 2012 Flare in the 800 – 2000 MHz Range by Marian Karlicky et al

2022-09-06

The solar radio spikes can provide detailed information about plasma processes in solar flares on kinetic scales. Among them, the decimetric spikes belong to the most interesting ones because they are recorded in some cases close to the starting frequency of Type-III bursts and in relation to hard X-ray emissions. Stepanov et al. (1999) and Bárta and Karlický (2001) presented models where spike frequencies correspond to those of the upper-hybrid […]

### PIC simulations of harmonic maser emissions by Ning et al.*

2021-11-23

Electron cyclotron maser emission (ECME) represents a major class of coherent emission mechanism of solar radio bursts. ECME usually occurs in strongly magnetized plasmas with the frequency ratio $\omega_{pe} / \Omega_{ce} < 1$, induced by energetic electrons with $\partial f /\partial v >0$, where $f$ represents the velocity distribution function. In solar active regions, this mechanism has been applied to millisecond spikes which are characterized by high brightness temperatures, short […]

### First Frequency-time-resolved Imaging Spectroscopy Observations of Solar Radio Spikes by D. L. Clarkson et al.*

2021-10-12

Solar radio spikes are short duration, narrowband radio bursts that are signature of the acceleration of non-thermal electrons in solar flares. They are observed over a wide range of frequencies from the tens of MHz (Melnik et al. 2014) to the GHz range (Benz et al. 1992), and have some of the shortest durations and narrow bandwidths of any solar radio bursts. The origin of spikes is not fully understood. […]

### Narrowband Spikes Observed during the 2013 November 7 Flare by M. Karlicky et al.

2021-06-22

Narrowband dm-spikes belong to the most interesting fine structures of solar radio bursts that are closely connected to primary flare energy-release processes (Krueger 1979) and observed in some cases near the Type III burst starting frequency. They occur in clouds of narrowband bursts with a typical duration less than 100 ms, frequency relative bandwidth 1-3 %, and brightness temperature up to $10^{15}$ K. For them several radio emission models were suggested. Earlier models suggested […]

### Harmonic Electron Cyclotron Maser Emission Excited by Energetic Electrons Traveling inside a Coronal Loop by M. Yousefzadeh et al.*

2021-04-27

Solar spikes are radio bursts closely associated with the impulsive stage of solar flares. They are characterized by extremely high brightness temperature of up to 1015 K, narrow-band, and short duration. Thousands of spikes could exist in an event. This leads researchers to suggest that solar spikes represent elementary energy release events during solar flares. Earlier studies have suggested the electron-cyclotron-maser emission (ECME) driven by energetic electrons with the loss-cone […]

### Detection of Spike-like structures near the front of Type II radio bursts by S. Armatas et al.*

2019-07-02

Type II solar radio bursts are the result of energetic electrons accelerated by a shock. This kind of burst appears on dynamic spectra as lanes which drift slowly from high to lower frequencies. Often, we observe a fundamental – harmonic structure, which sometimes exhibits a division on each band called band-split.  Fine structures are emissions with short duration and bandwidth embedded within all types of radio bursts and constitute a […]

### Scaling-laws of Radio Spike Bursts and Their Constraints on New Solar Radio Telescopes by Baolin Tan et al.

2019-06-18

Radio observation is one of the most important methods in solar physics and space science. Sometimes, it is almost the sole approach to observing physical processes such as the acceleration, emission, and propagation of non-thermal energetic particles, etc. Long-term observation and study have revealed that a strong solar radio burst is always composed of many small bursts with different time-scales. Among them, a radio spike burst is the smallest one, […]