We here propose that the large scale superluminal ejections observed in the galactic microquasar GRS 1915+105 during radio flare events are produced by violent magnetic reconnection episodes in the corona just above the inner edge of the magnetized accretion disk that surrounds the central \sim 10 M _ { \odot } 
black hole .
The process occurs when a large scale magnetic field is established by turbulent dynamo in the inner disk region with a ratio between the gas + radiation and the magnetic pressures \beta \simeq 1 , implying a magnetic field intensity of \sim 7 \times 10 ^ { 8 } G. During this process , substantial angular momentum is removed from the disk by the wind generated by the vertical magnetic flux therefore increasing the disk mass accretion to a value near ( but below ) the critical one ( \dot { M } \sim 10 ^ { 19 } g s ^ { -1 } ) .
Part of the magnetic energy released by reconnection heats the coronal gas ( T _ { c } \lesssim 5 \times 10 ^ { 8 } K ) that produces a steep , soft X-ray spectrum with luminosity L _ { X } \simeq 10 ^ { 39 } erg s ^ { -1 } , in consistency with observations .
The remaining magnetic energy released goes to accelerate the particles to relativistic velocities ( v \sim v _ { A } \sim c , where v _ { A } is the Alfvén speed ) in the reconnection site through first-order Fermi processes .
In this context , two possible mechanisms have been examined which produce power-law electron distributions N ( E ) \propto E ^ { - \alpha _ { E } } , with \alpha _ { E } = 5 / 2 , 2 , and corresponding synchrotron radio power-law spectra with spectral indices which are compatible with that observed during the flares ( S _ { \nu } \propto \nu ^ { -0.75 , -0.5 } ) .